resolved conflicts for merge of 8995e140 to lmp-mr1-wfc-dev

Change-Id: I21ffad3247858dc072964a5fa4beb609010c2b1a

5 files changed, 85 insertions, 93 deletions

diff --git a/services/core/java/com/android/server/am/ActivityManagerService.java b/services/core/java/com/android/server/am/ActivityManagerService.java
index 40bcf8e..e8f3757 100755
--- a/services/core/java/com/android/server/am/ActivityManagerService.java
+++ b/services/core/java/com/android/server/am/ActivityManagerService.java
@@ -2358,7 +2358,7 @@ public final class ActivityManagerService extends ActivityManagerNative
         return mAppBindArgs;
     }
 
-    final void setFocusedActivityLocked(ActivityRecord r) {
+    final void setFocusedActivityLocked(ActivityRecord r, String reason) {
         if (mFocusedActivity != r) {
             if (DEBUG_FOCUS) Slog.d(TAG, "setFocusedActivityLocked: r=" + r);
             mFocusedActivity = r;
@@ -2367,7 +2367,7 @@ public final class ActivityManagerService extends ActivityManagerNative
             } else {
                 finishRunningVoiceLocked();
             }
-            mStackSupervisor.setFocusedStack(r);
+            mStackSupervisor.setFocusedStack(r, reason + " setFocusedActivity");
             if (r != null) {
                 mWindowManager.setFocusedApp(r.appToken, true);
             }
@@ -2391,7 +2391,7 @@ public final class ActivityManagerService extends ActivityManagerNative
             if (stack != null) {
                 ActivityRecord r = stack.topRunningActivityLocked(null);
                 if (r != null) {
-                    setFocusedActivityLocked(r);
+                    setFocusedActivityLocked(r, "setFocusedStack");
                 }
             }
         }
@@ -2435,7 +2435,7 @@ public final class ActivityManagerService extends ActivityManagerNative
         mHandler.sendMessage(msg);
     }
 
-    private final int updateLruProcessInternalLocked(ProcessRecord app, long now, int index,
+    private int updateLruProcessInternalLocked(ProcessRecord app, long now, int index,
             String what, Object obj, ProcessRecord srcApp) {
         app.lastActivityTime = now;
 
@@ -3109,7 +3109,7 @@ public final class ActivityManagerService extends ActivityManagerNative
         return intent;
     }
 
-    boolean startHomeActivityLocked(int userId) {
+    boolean startHomeActivityLocked(int userId, String reason) {
         if (mFactoryTest == FactoryTest.FACTORY_TEST_LOW_LEVEL
                 && mTopAction == null) {
             // We are running in factory test mode, but unable to find
@@ -3131,7 +3131,7 @@ public final class ActivityManagerService extends ActivityManagerNative
                     aInfo.applicationInfo.uid, true);
             if (app == null || app.instrumentationClass == null) {
                 intent.setFlags(intent.getFlags() | Intent.FLAG_ACTIVITY_NEW_TASK);
-                mStackSupervisor.startHomeActivity(intent, aInfo);
+                mStackSupervisor.startHomeActivity(intent, aInfo, reason);
             }
         }
 
@@ -6203,7 +6203,7 @@ public final class ActivityManagerService extends ActivityManagerNative
                     startProcessLocked(procs.get(ip), "on-hold", null);
                 }
             }
-            
+
             if (mFactoryTest != FactoryTest.FACTORY_TEST_LOW_LEVEL) {
                 // Start looking for apps that are abusing wake locks.
                 Message nmsg = mHandler.obtainMessage(CHECK_EXCESSIVE_WAKE_LOCKS_MSG);
@@ -6343,7 +6343,7 @@ public final class ActivityManagerService extends ActivityManagerNative
         synchronized (this) {
             ActivityStack stack = ActivityRecord.getStackLocked(token);
             if (stack != null) {
-                stack.activityDestroyedLocked(token);
+                stack.activityDestroyedLocked(token, "activityDestroyed");
             }
         }
     }
@@ -6454,7 +6454,7 @@ public final class ActivityManagerService extends ActivityManagerNative
                 throw new IllegalArgumentException("File descriptors passed in options");
             }
         }
-        
+
         synchronized(this) {
             int callingUid = Binder.getCallingUid();
             int origUserId = userId;
@@ -6484,7 +6484,7 @@ public final class ActivityManagerService extends ActivityManagerNative
 
                 return getIntentSenderLocked(type, packageName, callingUid, userId,
                         token, resultWho, requestCode, intents, resolvedTypes, flags, options);
-                
+
             } catch (RemoteException e) {
                 throw new SecurityException(e);
             }
@@ -8536,7 +8536,7 @@ public final class ActivityManagerService extends ActivityManagerNative
             if (prev != null && prev.isRecentsActivity()) {
                 task.setTaskToReturnTo(ActivityRecord.RECENTS_ACTIVITY_TYPE);
             }
-            mStackSupervisor.findTaskToMoveToFrontLocked(task, flags, options);
+            mStackSupervisor.findTaskToMoveToFrontLocked(task, flags, options, "moveTaskToFront");
         } finally {
             Binder.restoreCallingIdentity(origId);
         }
@@ -8565,7 +8565,7 @@ public final class ActivityManagerService extends ActivityManagerNative
                 }
                 final long origId = Binder.clearCallingIdentity();
                 try {
-                    stack.moveTaskToBackLocked(taskId, null);
+                    stack.moveTaskToBackLocked(taskId);
                 } finally {
                     Binder.restoreCallingIdentity(origId);
                 }
@@ -8595,7 +8595,7 @@ public final class ActivityManagerService extends ActivityManagerNative
                         mStackSupervisor.showLockTaskToast();
                         return false;
                     }
-                    return ActivityRecord.getStackLocked(token).moveTaskToBackLocked(taskId, null);
+                    return ActivityRecord.getStackLocked(token).moveTaskToBackLocked(taskId);
                 }
             } finally {
                 Binder.restoreCallingIdentity(origId);
@@ -8687,7 +8687,7 @@ public final class ActivityManagerService extends ActivityManagerNative
             try {
                 if (DEBUG_STACK) Slog.d(TAG, "moveTaskToStack: moving task=" + taskId + " to stackId="
                         + stackId + " toTop=" + toTop);
-                mStackSupervisor.moveTaskToStack(taskId, stackId, toTop);
+                mStackSupervisor.moveTaskToStackLocked(taskId, stackId, toTop);
             } finally {
                 Binder.restoreCallingIdentity(ident);
             }
@@ -8793,7 +8793,8 @@ public final class ActivityManagerService extends ActivityManagerNative
                                     || (task != mStackSupervisor.getFocusedStack().topTask()))) {
                         throw new IllegalArgumentException("Invalid task, not in foreground");
                     }
-                    mStackSupervisor.setLockTaskModeLocked(task, !isSystemInitiated);
+                    mStackSupervisor.setLockTaskModeLocked(task, !isSystemInitiated,
+                            "startLockTask");
                 }
             }
         } finally {
@@ -8878,7 +8879,7 @@ public final class ActivityManagerService extends ActivityManagerNative
             Log.d(TAG, "stopLockTaskMode");
             // Stop lock task
             synchronized (this) {
-                mStackSupervisor.setLockTaskModeLocked(null, false);
+                mStackSupervisor.setLockTaskModeLocked(null, false, "stopLockTask");
             }
         } finally {
             Binder.restoreCallingIdentity(ident);
@@ -11338,7 +11339,7 @@ public final class ActivityManagerService extends ActivityManagerNative
 
             // Start up initial activity.
             mBooting = true;
-            startHomeActivityLocked(mCurrentUserId);
+            startHomeActivityLocked(mCurrentUserId, "systemReady");
 
             try {
                 if (AppGlobals.getPackageManager().hasSystemUidErrors()) {
@@ -18885,7 +18886,7 @@ public final class ActivityManagerService extends ActivityManagerNative
                     return true;
                 }
 
-                mStackSupervisor.setLockTaskModeLocked(null, false);
+                mStackSupervisor.setLockTaskModeLocked(null, false, "startUser");
 
                 final UserInfo userInfo = getUserManagerLocked().getUserInfo(userId);
                 if (userInfo == null) {
@@ -19142,7 +19143,7 @@ public final class ActivityManagerService extends ActivityManagerNative
     void moveUserToForeground(UserStartedState uss, int oldUserId, int newUserId) {
         boolean homeInFront = mStackSupervisor.switchUserLocked(newUserId, uss);
         if (homeInFront) {
-            startHomeActivityLocked(newUserId);
+            startHomeActivityLocked(newUserId, "moveUserToFroreground");
         } else {
             mStackSupervisor.resumeTopActivitiesLocked();
         }
diff --git a/services/core/java/com/android/server/am/ActivityRecord.java b/services/core/java/com/android/server/am/ActivityRecord.java
index 0b49c9c..b1b2a5c 100755
--- a/services/core/java/com/android/server/am/ActivityRecord.java
+++ b/services/core/java/com/android/server/am/ActivityRecord.java
@@ -516,7 +516,7 @@ final class ActivityRecord {
     void setTask(TaskRecord newTask, TaskRecord taskToAffiliateWith) {
         if (task != null && task.removeActivity(this)) {
             if (task != newTask) {
-                task.stack.removeTask(task);
+                task.stack.removeTask(task, "setTask");
             } else {
                 Slog.d(TAG, "!!! REMOVE THIS LOG !!! setTask: nearly removed stack=" +
                         (newTask == null ? null : newTask.stack));
diff --git a/services/core/java/com/android/server/am/ActivityStack.java b/services/core/java/com/android/server/am/ActivityStack.java
index c3a344f..7908da0 100755
--- a/services/core/java/com/android/server/am/ActivityStack.java
+++ b/services/core/java/com/android/server/am/ActivityStack.java
@@ -291,7 +291,7 @@ final class ActivityStack {
                     // so we need to be conservative and assume it isn't.
                     Slog.w(TAG, "Activity destroy timeout for " + r);
                     synchronized (mService) {
-                        activityDestroyedLocked(r != null ? r.appToken : null);
+                        activityDestroyedLocked(r != null ? r.appToken : null, "destroyTimeout");
                     }
                 } break;
                 case STOP_TIMEOUT_MSG: {
@@ -473,10 +473,10 @@ final class ActivityStack {
                 mActivityContainer.mActivityDisplay.mDisplayId == Display.DEFAULT_DISPLAY;
     }
 
-    final void moveToFront() {
+    final void moveToFront(String reason) {
         if (isAttached()) {
             if (isOnHomeDisplay()) {
-                mStackSupervisor.moveHomeStack(isHomeStack());
+                mStackSupervisor.moveHomeStack(isHomeStack(), reason);
             }
             mStacks.remove(this);
             mStacks.add(this);
@@ -1496,7 +1496,7 @@ final class ActivityStack {
             final int returnTaskType = prevTask == null || !prevTask.isOverHomeStack() ?
                     HOME_ACTIVITY_TYPE : prevTask.getTaskToReturnTo();
             return isOnHomeDisplay() &&
-                    mStackSupervisor.resumeHomeStackTask(returnTaskType, prev);
+                    mStackSupervisor.resumeHomeStackTask(returnTaskType, prev, "noMoreActivities");
         }
 
         next.delayedResume = false;
@@ -1532,7 +1532,7 @@ final class ActivityStack {
                 final int returnTaskType = prevTask == null || !prevTask.isOverHomeStack() ?
                         HOME_ACTIVITY_TYPE : prevTask.getTaskToReturnTo();
                 return isOnHomeDisplay() &&
-                        mStackSupervisor.resumeHomeStackTask(returnTaskType, prev);
+                        mStackSupervisor.resumeHomeStackTask(returnTaskType, prev, "prevFinished");
             }
         }
 
@@ -1817,11 +1817,8 @@ final class ActivityStack {
                     next.app.thread.scheduleNewIntent(next.newIntents, next.appToken);
                 }
 
-                EventLog.writeEvent(EventLogTags.AM_RESUME_ACTIVITY,
-                        next.userId, System.identityHashCode(next),
-                        next.task.taskId, next.shortComponentName + " top="
-                                + mStacks.get(mStacks.size() - 1).mStackId + " Callers="
-                                + Debug.getCallers(6));
+                EventLog.writeEvent(EventLogTags.AM_RESUME_ACTIVITY, next.userId,
+                        System.identityHashCode(next), next.task.taskId, next.shortComponentName);
 
                 next.sleeping = false;
                 mService.showAskCompatModeDialogLocked(next);
@@ -2468,18 +2465,19 @@ final class ActivityStack {
         r.addResultLocked(null, resultWho, requestCode, resultCode, data);
     }
 
-    private void adjustFocusedActivityLocked(ActivityRecord r) {
+    private void adjustFocusedActivityLocked(ActivityRecord r, String reason) {
         if (mStackSupervisor.isFrontStack(this) && mService.mFocusedActivity == r) {
             ActivityRecord next = topRunningActivityLocked(null);
             if (next != r) {
                 final TaskRecord task = r.task;
                 if (r.frontOfTask && task == topTask() && task.isOverHomeStack()) {
-                    mStackSupervisor.moveHomeStackTaskToTop(task.getTaskToReturnTo());
+                    mStackSupervisor.moveHomeStackTaskToTop(task.getTaskToReturnTo(),
+                            reason + " adjustFocus");
                 }
             }
             ActivityRecord top = mStackSupervisor.topRunningActivityLocked();
             if (top != null) {
-                mService.setFocusedActivityLocked(top);
+                mService.setFocusedActivityLocked(top, reason + " adjustTopFocus");
             }
         }
     }
@@ -2503,7 +2501,7 @@ final class ActivityStack {
         }
 
         if (r.app != null && r.app.thread != null) {
-            adjustFocusedActivityLocked(r);
+            adjustFocusedActivityLocked(r, "stopActivity");
             r.resumeKeyDispatchingLocked();
             try {
                 r.stopped = false;
@@ -2707,7 +2705,7 @@ final class ActivityStack {
 
         r.pauseKeyDispatchingLocked();
 
-        adjustFocusedActivityLocked(r);
+        adjustFocusedActivityLocked(r, "finishActivity");
 
         finishActivityResultsLocked(r, resultCode, resultData);
 
@@ -3010,7 +3008,7 @@ final class ActivityStack {
         r.finishLaunchTickingLocked();
     }
 
-    private void removeActivityFromHistoryLocked(ActivityRecord r) {
+    private void removeActivityFromHistoryLocked(ActivityRecord r, String reason) {
         mStackSupervisor.removeChildActivityContainers(r);
         finishActivityResultsLocked(r, Activity.RESULT_CANCELED, null);
         r.makeFinishing();
@@ -3035,9 +3033,9 @@ final class ActivityStack {
                     "removeActivityFromHistoryLocked: last activity removed from " + this);
             if (mStackSupervisor.isFrontStack(this) && task == topTask() &&
                     task.isOverHomeStack()) {
-                mStackSupervisor.moveHomeStackTaskToTop(task.getTaskToReturnTo());
+                mStackSupervisor.moveHomeStackTaskToTop(task.getTaskToReturnTo(), reason);
             }
-            removeTask(task);
+            removeTask(task, reason);
         }
         cleanUpActivityServicesLocked(r);
         r.removeUriPermissionsLocked();
@@ -3202,7 +3200,7 @@ final class ActivityStack {
                 // up.
                 //Slog.w(TAG, "Exception thrown during finish", e);
                 if (r.finishing) {
-                    removeActivityFromHistoryLocked(r);
+                    removeActivityFromHistoryLocked(r, reason + " exceptionInScheduleDestroy");
                     removedFromHistory = true;
                     skipDestroy = true;
                 }
@@ -3232,7 +3230,7 @@ final class ActivityStack {
         } else {
             // remove this record from the history.
             if (r.finishing) {
-                removeActivityFromHistoryLocked(r);
+                removeActivityFromHistoryLocked(r, reason + " hadNoApp");
                 removedFromHistory = true;
             } else {
                 if (DEBUG_STATES) Slog.v(TAG, "Moving to DESTROYED: " + r + " (no app)");
@@ -3251,7 +3249,7 @@ final class ActivityStack {
         return removedFromHistory;
     }
 
-    final void activityDestroyedLocked(IBinder token) {
+    final void activityDestroyedLocked(IBinder token, String reason) {
         final long origId = Binder.clearCallingIdentity();
         try {
             ActivityRecord r = ActivityRecord.forToken(token);
@@ -3263,7 +3261,7 @@ final class ActivityStack {
             if (isInStackLocked(token) != null) {
                 if (r.state == ActivityState.DESTROYING) {
                     cleanUpActivityLocked(r, true, false);
-                    removeActivityFromHistoryLocked(r);
+                    removeActivityFromHistoryLocked(r, reason);
                 }
             }
             mStackSupervisor.resumeTopActivitiesLocked();
@@ -3399,7 +3397,7 @@ final class ActivityStack {
                                 mService.updateUsageStats(r, false);
                             }
                         }
-                        removeActivityFromHistoryLocked(r);
+                        removeActivityFromHistoryLocked(r, "appDied");
 
                     } else {
                         // We have the current state for this activity, so
@@ -3468,15 +3466,16 @@ final class ActivityStack {
         }
     }
 
-    final void moveTaskToFrontLocked(TaskRecord tr, ActivityRecord reason, Bundle options) {
+    final void moveTaskToFrontLocked(TaskRecord tr, ActivityRecord source, Bundle options,
+            String reason) {
         if (DEBUG_SWITCH) Slog.v(TAG, "moveTaskToFront: " + tr);
 
         final int numTasks = mTaskHistory.size();
         final int index = mTaskHistory.indexOf(tr);
         if (numTasks == 0 || index < 0)  {
             // nothing to do!
-            if (reason != null &&
-                    (reason.intent.getFlags()&Intent.FLAG_ACTIVITY_NO_ANIMATION) != 0) {
+            if (source != null &&
+                    (source.intent.getFlags()&Intent.FLAG_ACTIVITY_NO_ANIMATION) != 0) {
                 ActivityOptions.abort(options);
             } else {
                 updateTransitLocked(AppTransition.TRANSIT_TASK_TO_FRONT, options);
@@ -3487,11 +3486,11 @@ final class ActivityStack {
         // Shift all activities with this task up to the top
         // of the stack, keeping them in the same internal order.
         insertTaskAtTop(tr);
-        moveToFront();
+        moveToFront(reason);
 
         if (DEBUG_TRANSITION) Slog.v(TAG, "Prepare to front transition: task=" + tr);
-        if (reason != null &&
-                (reason.intent.getFlags()&Intent.FLAG_ACTIVITY_NO_ANIMATION) != 0) {
+        if (source != null &&
+                (source.intent.getFlags()&Intent.FLAG_ACTIVITY_NO_ANIMATION) != 0) {
             mWindowManager.prepareAppTransition(AppTransition.TRANSIT_NONE, false);
             ActivityRecord r = topRunningActivityLocked(null);
             if (r != null) {
@@ -3521,7 +3520,7 @@ final class ActivityStack {
      * @param taskId The taskId to collect and move to the bottom.
      * @return Returns true if the move completed, false if not.
      */
-    final boolean moveTaskToBackLocked(int taskId, ActivityRecord reason) {
+    final boolean moveTaskToBackLocked(int taskId) {
         final TaskRecord tr = taskForIdLocked(taskId);
         if (tr == null) {
             Slog.i(TAG, "moveTaskToBack: bad taskId=" + taskId);
@@ -3576,16 +3575,7 @@ final class ActivityStack {
             }
         }
 
-        if (reason != null &&
-                (reason.intent.getFlags() & Intent.FLAG_ACTIVITY_NO_ANIMATION) != 0) {
-            mWindowManager.prepareAppTransition(AppTransition.TRANSIT_NONE, false);
-            ActivityRecord r = topRunningActivityLocked(null);
-            if (r != null) {
-                mNoAnimActivities.add(r);
-            }
-        } else {
-            mWindowManager.prepareAppTransition(AppTransition.TRANSIT_TASK_TO_BACK, false);
-        }
+        mWindowManager.prepareAppTransition(AppTransition.TRANSIT_TASK_TO_BACK, false);
         mWindowManager.moveTaskToBottom(taskId);
 
         if (VALIDATE_TOKENS) {
@@ -3600,7 +3590,7 @@ final class ActivityStack {
             }
             final int taskToReturnTo = tr.getTaskToReturnTo();
             tr.setTaskToReturnTo(APPLICATION_ACTIVITY_TYPE);
-            return mStackSupervisor.resumeHomeStackTask(taskToReturnTo, null);
+            return mStackSupervisor.resumeHomeStackTask(taskToReturnTo, null, "moveTaskToBack");
         }
 
         mStackSupervisor.resumeTopActivitiesLocked();
@@ -4042,7 +4032,7 @@ final class ActivityStack {
         return starting;
     }
 
-    void removeTask(TaskRecord task) {
+    void removeTask(TaskRecord task, String reason) {
         mStackSupervisor.endLockTaskModeIfTaskEnding(task);
         mWindowManager.removeTask(task.taskId);
         final ActivityRecord r = mResumedActivity;
@@ -4080,7 +4070,7 @@ final class ActivityStack {
         if (mTaskHistory.isEmpty()) {
             if (DEBUG_STACK) Slog.i(TAG, "removeTask: moving to back stack=" + this);
             if (isOnHomeDisplay()) {
-                mStackSupervisor.moveHomeStack(!isHomeStack());
+                mStackSupervisor.moveHomeStack(!isHomeStack(), reason + " leftTaskHistoryEmpty");
             }
             if (mStacks != null) {
                 mStacks.remove(this);
diff --git a/services/core/java/com/android/server/am/ActivityStackSupervisor.java b/services/core/java/com/android/server/am/ActivityStackSupervisor.java
index 5c8e191..32787d8 100644
--- a/services/core/java/com/android/server/am/ActivityStackSupervisor.java
+++ b/services/core/java/com/android/server/am/ActivityStackSupervisor.java
@@ -398,7 +398,7 @@ public final class ActivityStackSupervisor implements DisplayListener {
         return false;
     }
 
-    void moveHomeStack(boolean toFront) {
+    void moveHomeStack(boolean toFront, String reason) {
         ArrayList<ActivityStack> stacks = mHomeStack.mStacks;
         final int topNdx = stacks.size() - 1;
         if (topNdx <= 0) {
@@ -416,7 +416,7 @@ public final class ActivityStackSupervisor implements DisplayListener {
         }
         EventLog.writeEvent(EventLogTags.AM_HOME_STACK_MOVED,
                 mCurrentUser, toFront ? 1 : 0, stacks.get(topNdx).getStackId(),
-                mFocusedStack == null ? -1 : mFocusedStack.getStackId());
+                mFocusedStack == null ? -1 : mFocusedStack.getStackId(), reason);
 
         if (mService.mBooting || !mService.mBooted) {
             final ActivityRecord r = topRunningActivityLocked();
@@ -426,16 +426,16 @@ public final class ActivityStackSupervisor implements DisplayListener {
         }
     }
 
-    void moveHomeStackTaskToTop(int homeStackTaskType) {
+    void moveHomeStackTaskToTop(int homeStackTaskType, String reason) {
         if (homeStackTaskType == RECENTS_ACTIVITY_TYPE) {
             mWindowManager.showRecentApps();
             return;
         }
-        moveHomeStack(true);
+        moveHomeStack(true, reason);
         mHomeStack.moveHomeStackTaskToTop(homeStackTaskType);
     }
 
-    boolean resumeHomeStackTask(int homeStackTaskType, ActivityRecord prev) {
+    boolean resumeHomeStackTask(int homeStackTaskType, ActivityRecord prev, String reason) {
         if (!mService.mBooting && !mService.mBooted) {
             // Not ready yet!
             return false;
@@ -445,7 +445,7 @@ public final class ActivityStackSupervisor implements DisplayListener {
             mWindowManager.showRecentApps();
             return false;
         }
-        moveHomeStackTaskToTop(homeStackTaskType);
+        moveHomeStackTaskToTop(homeStackTaskType, reason);
         if (prev != null) {
             prev.task.setTaskToReturnTo(APPLICATION_ACTIVITY_TYPE);
         }
@@ -453,10 +453,10 @@ public final class ActivityStackSupervisor implements DisplayListener {
         ActivityRecord r = mHomeStack.topRunningActivityLocked(null);
         // if (r != null && (r.isHomeActivity() || r.isRecentsActivity())) {
         if (r != null && r.isHomeActivity()) {
-            mService.setFocusedActivityLocked(r);
+            mService.setFocusedActivityLocked(r, reason);
             return resumeTopActivitiesLocked(mHomeStack, prev, null);
         }
-        return mService.startHomeActivityLocked(mCurrentUser);
+        return mService.startHomeActivityLocked(mCurrentUser, reason);
     }
 
     TaskRecord anyTaskForIdLocked(int id) {
@@ -828,8 +828,8 @@ public final class ActivityStackSupervisor implements DisplayListener {
         return aInfo;
     }
 
-    void startHomeActivity(Intent intent, ActivityInfo aInfo) {
-        moveHomeStackTaskToTop(HOME_ACTIVITY_TYPE);
+    void startHomeActivity(Intent intent, ActivityInfo aInfo, String reason) {
+        moveHomeStackTaskToTop(HOME_ACTIVITY_TYPE, reason);
         startActivityLocked(null, intent, null, aInfo, null, null, null, null, 0, 0, 0, null,
                 0, 0, 0, null, false, null, null, null);
     }
@@ -1581,7 +1581,7 @@ public final class ActivityStackSupervisor implements DisplayListener {
         return mHomeStack;
     }
 
-    void setFocusedStack(ActivityRecord r) {
+    void setFocusedStack(ActivityRecord r, String reason) {
         if (r != null) {
             final TaskRecord task = r.task;
             boolean isHomeActivity = !r.isApplicationActivity();
@@ -1592,7 +1592,7 @@ public final class ActivityStackSupervisor implements DisplayListener {
                 final ActivityRecord parent = task.stack.mActivityContainer.mParentActivity;
                 isHomeActivity = parent != null && parent.isHomeActivity();
             }
-            moveHomeStack(isHomeActivity);
+            moveHomeStack(isHomeActivity, reason);
         }
     }
 
@@ -1840,7 +1840,7 @@ public final class ActivityStackSupervisor implements DisplayListener {
                     targetStack.mLastPausedActivity = null;
                     if (DEBUG_TASKS) Slog.d(TAG, "Bring to front target: " + targetStack
                             + " from " + intentActivity);
-                    targetStack.moveToFront();
+                    targetStack.moveToFront("intentActivityFound");
                     if (intentActivity.task.intent == null) {
                         // This task was started because of movement of
                         // the activity based on affinity...  now that we
@@ -1869,7 +1869,8 @@ public final class ActivityStackSupervisor implements DisplayListener {
                                 intentActivity.setTaskToAffiliateWith(sourceRecord.task);
                             }
                             movedHome = true;
-                            targetStack.moveTaskToFrontLocked(intentActivity.task, r, options);
+                            targetStack.moveTaskToFrontLocked(intentActivity.task, r, options,
+                                    "bringingFoundTaskToFront");
                             if ((launchFlags &
                                     (FLAG_ACTIVITY_NEW_TASK | FLAG_ACTIVITY_TASK_ON_HOME))
                                     == (FLAG_ACTIVITY_NEW_TASK | FLAG_ACTIVITY_TASK_ON_HOME)) {
@@ -2067,7 +2068,7 @@ public final class ActivityStackSupervisor implements DisplayListener {
             newTask = true;
             targetStack = adjustStackFocus(r, newTask);
             if (!launchTaskBehind) {
-                targetStack.moveToFront();
+                targetStack.moveToFront("startingNewTask");
             }
             if (reuseTask == null) {
                 r.setTask(targetStack.createTaskRecord(getNextTaskId(),
@@ -2096,10 +2097,10 @@ public final class ActivityStackSupervisor implements DisplayListener {
                 return ActivityManager.START_RETURN_LOCK_TASK_MODE_VIOLATION;
             }
             targetStack = sourceTask.stack;
-            targetStack.moveToFront();
+            targetStack.moveToFront("sourceStackToFront");
             final TaskRecord topTask = targetStack.topTask();
             if (topTask != sourceTask) {
-                targetStack.moveTaskToFrontLocked(sourceTask, r, options);
+                targetStack.moveTaskToFrontLocked(sourceTask, r, options, "sourceTaskToFront");
             }
             if (!addingToTask && (launchFlags&Intent.FLAG_ACTIVITY_CLEAR_TOP) != 0) {
                 // In this case, we are adding the activity to an existing
@@ -2153,7 +2154,7 @@ public final class ActivityStackSupervisor implements DisplayListener {
                 return ActivityManager.START_RETURN_LOCK_TASK_MODE_VIOLATION;
             }
             targetStack = inTask.stack;
-            targetStack.moveTaskToFrontLocked(inTask, r, options);
+            targetStack.moveTaskToFrontLocked(inTask, r, options, "inTaskToFront");
 
             // Check whether we should actually launch the new activity in to the task,
             // or just reuse the current activity on top.
@@ -2189,7 +2190,7 @@ public final class ActivityStackSupervisor implements DisplayListener {
             // of a new task...  just put it in the top task, though these days
             // this case should never happen.
             targetStack = adjustStackFocus(r, newTask);
-            targetStack.moveToFront();
+            targetStack.moveToFront("addingToTopTask");
             ActivityRecord prev = targetStack.topActivity();
             r.setTask(prev != null ? prev.task : targetStack.createTaskRecord(getNextTaskId(),
                             r.info, intent, null, null, true), null);
@@ -2212,7 +2213,7 @@ public final class ActivityStackSupervisor implements DisplayListener {
         targetStack.startActivityLocked(r, newTask, doResume, keepCurTransition, options);
         if (!launchTaskBehind) {
             // Don't set focus on an activity that's going to the back.
-            mService.setFocusedActivityLocked(r);
+            mService.setFocusedActivityLocked(r, "startedActivity");
         }
         return ActivityManager.START_SUCCESS;
     }
@@ -2509,7 +2510,7 @@ public final class ActivityStackSupervisor implements DisplayListener {
         }
     }
 
-    void findTaskToMoveToFrontLocked(TaskRecord task, int flags, Bundle options) {
+    void findTaskToMoveToFrontLocked(TaskRecord task, int flags, Bundle options, String reason) {
         if ((flags & ActivityManager.MOVE_TASK_NO_USER_ACTION) == 0) {
             mUserLeaving = true;
         }
@@ -2518,7 +2519,7 @@ public final class ActivityStackSupervisor implements DisplayListener {
             // we'll just indicate that this task returns to the home task.
             task.setTaskToReturnTo(HOME_ACTIVITY_TYPE);
         }
-        task.stack.moveTaskToFrontLocked(task, null, options);
+        task.stack.moveTaskToFrontLocked(task, null, options, reason);
         if (DEBUG_STACK) Slog.d(TAG, "findTaskToMoveToFront: moved to front of stack="
                 + task.stack);
     }
@@ -2643,7 +2644,7 @@ public final class ActivityStackSupervisor implements DisplayListener {
             // display.
             stack = getStack(createStackOnDisplay(getNextStackId(), Display.DEFAULT_DISPLAY));
             // Restore home stack to top.
-            moveHomeStack(true);
+            moveHomeStack(true, "restoreRecentTask");
             if (DEBUG_RECENTS)
                 Slog.v(TAG, "Created stack=" + stack + " for recents restoration.");
         }
@@ -2670,7 +2671,7 @@ public final class ActivityStackSupervisor implements DisplayListener {
         return true;
     }
 
-    void moveTaskToStack(int taskId, int stackId, boolean toTop) {
+    void moveTaskToStackLocked(int taskId, int stackId, boolean toTop) {
         final TaskRecord task = anyTaskForIdLocked(taskId);
         if (task == null) {
             return;
@@ -2680,7 +2681,7 @@ public final class ActivityStackSupervisor implements DisplayListener {
             Slog.w(TAG, "moveTaskToStack: no stack for id=" + stackId);
             return;
         }
-        task.stack.removeTask(task);
+        task.stack.removeTask(task, "moveTaskToStack");
         stack.addTask(task, toTop, true);
         mWindowManager.addTask(taskId, stackId, toTop);
         resumeTopActivitiesLocked();
@@ -3046,14 +3047,14 @@ public final class ActivityStackSupervisor implements DisplayListener {
         }
         final boolean homeInFront = stack.isHomeStack();
         if (stack.isOnHomeDisplay()) {
-            moveHomeStack(homeInFront);
+            moveHomeStack(homeInFront, "switchUserOnHomeDisplay");
             TaskRecord task = stack.topTask();
             if (task != null) {
                 mWindowManager.moveTaskToTop(task.taskId);
             }
         } else {
             // Stack was moved to another display while user was swapped out.
-            resumeHomeStackTask(HOME_ACTIVITY_TYPE, null);
+            resumeHomeStackTask(HOME_ACTIVITY_TYPE, null, "switchUserOnOtherDisplay");
         }
         return homeInFront;
     }
@@ -3454,7 +3455,7 @@ public final class ActivityStackSupervisor implements DisplayListener {
         mLockTaskNotify.showToast(mLockTaskIsLocked);
     }
 
-    void setLockTaskModeLocked(TaskRecord task, boolean isLocked) {
+    void setLockTaskModeLocked(TaskRecord task, boolean isLocked, String reason) {
         if (task == null) {
             // Take out of lock task mode if necessary
             if (mLockTaskModeTask != null) {
@@ -3471,7 +3472,7 @@ public final class ActivityStackSupervisor implements DisplayListener {
             return;
         }
         mLockTaskModeTask = task;
-        findTaskToMoveToFrontLocked(task, 0, null);
+        findTaskToMoveToFrontLocked(task, 0, null, reason);
         resumeTopActivitiesLocked();
 
         final Message lockTaskMsg = Message.obtain();
diff --git a/services/core/java/com/android/server/am/EventLogTags.logtags b/services/core/java/com/android/server/am/EventLogTags.logtags
index 41499be..c376744 100644
--- a/services/core/java/com/android/server/am/EventLogTags.logtags
+++ b/services/core/java/com/android/server/am/EventLogTags.logtags
@@ -94,4 +94,4 @@ option java_package com.android.server.am
 30043 am_focused_activity (User|1|5),(Component Name|3)
 
 # Home Stack brought to front or rear
-30044 am_home_stack_moved (User|1|5),(To Front|1|5),(Top Stack Id|1|5),(Focused Stack Id|1|5)
+30044 am_home_stack_moved (User|1|5),(To Front|1|5),(Top Stack Id|1|5),(Focused Stack Id|1|5),(Reason|3)