3 files changed, 46 insertions, 0 deletions

diff --git a/core/java/android/os/PowerManager.java b/core/java/android/os/PowerManager.java
index d52dd30..e303f61 100644
--- a/core/java/android/os/PowerManager.java
+++ b/core/java/android/os/PowerManager.java
@@ -205,6 +205,20 @@ public final class PowerManager {
     public static final int DOZE_WAKE_LOCK = 0x00000040;
 
     /**
+     * Wake lock level: Keep the device awake enough to allow drawing to occur.
+     * <p>
+     * This is used by the window manager to allow applications to draw while the
+     * system is dozing.  It currently has no effect unless the power manager is in
+     * the dozing state.
+     * </p><p>
+     * Requires the {@link android.Manifest.permission#DEVICE_POWER} permission.
+     * </p>
+     *
+     * {@hide}
+     */
+    public static final int DRAW_WAKE_LOCK = 0x00000080;
+
+    /**
      * Mask for the wake lock level component of a combined wake lock level and flags integer.
      *
      * @hide
@@ -489,6 +503,7 @@ public final class PowerManager {
             case FULL_WAKE_LOCK:
             case PROXIMITY_SCREEN_OFF_WAKE_LOCK:
             case DOZE_WAKE_LOCK:
+            case DRAW_WAKE_LOCK:
                 break;
             default:
                 throw new IllegalArgumentException("Must specify a valid wake lock level.");
diff --git a/core/java/android/view/IWindowSession.aidl b/core/java/android/view/IWindowSession.aidl
index d08ab46..fc0148f 100644
--- a/core/java/android/view/IWindowSession.aidl
+++ b/core/java/android/view/IWindowSession.aidl
@@ -194,4 +194,19 @@ interface IWindowSession {
     void onRectangleOnScreenRequested(IBinder token, in Rect rectangle);
 
     IWindowId getWindowId(IBinder window);
+
+    /**
+     * When the system is dozing in a low-power partially suspended state, pokes a short
+     * lived wake lock and ensures that the display is ready to accept the next frame
+     * of content drawn in the window.
+     *
+     * This mechanism is bound to the window rather than to the display manager or the
+     * power manager so that the system can ensure that the window is actually visible
+     * and prevent runaway applications from draining the battery.  This is similar to how
+     * FLAG_KEEP_SCREEN_ON works.
+     *
+     * This method is synchronous because it may need to acquire a wake lock before returning.
+     * The assumption is that this method will be called rather infrequently.
+     */
+    void pokeDrawLock(IBinder window);
 }
diff --git a/core/java/android/view/ViewRootImpl.java b/core/java/android/view/ViewRootImpl.java
index f392682..3baf3e0 100644
--- a/core/java/android/view/ViewRootImpl.java
+++ b/core/java/android/view/ViewRootImpl.java
@@ -47,6 +47,7 @@ import android.os.Handler;
 import android.os.Looper;
 import android.os.Message;
 import android.os.ParcelFileDescriptor;
+import android.os.PowerManager;
 import android.os.Process;
 import android.os.RemoteException;
 import android.os.SystemClock;
@@ -838,6 +839,7 @@ public final class ViewRootImpl implements ViewParent,
                 final int newDisplayState = mDisplay.getState();
                 if (oldDisplayState != newDisplayState) {
                     mAttachInfo.mDisplayState = newDisplayState;
+                    pokeDrawLockIfNeeded();
                     if (oldDisplayState != Display.STATE_UNKNOWN) {
                         final int oldScreenState = toViewScreenState(oldDisplayState);
                         final int newScreenState = toViewScreenState(newDisplayState);
@@ -868,6 +870,19 @@ public final class ViewRootImpl implements ViewParent,
         }
     };
 
+    void pokeDrawLockIfNeeded() {
+        final int displayState = mAttachInfo.mDisplayState;
+        if (mView != null && mAdded && mTraversalScheduled
+                && (displayState == Display.STATE_DOZE
+                        || displayState == Display.STATE_DOZE_SUSPEND)) {
+            try {
+                mWindowSession.pokeDrawLock(mWindow);
+            } catch (RemoteException ex) {
+                // System server died, oh well.
+            }
+        }
+    }
+
     @Override
     public void requestFitSystemWindows() {
         checkThread();
@@ -1042,6 +1057,7 @@ public final class ViewRootImpl implements ViewParent,
                 scheduleConsumeBatchedInput();
             }
             notifyRendererOfFramePending();
+            pokeDrawLockIfNeeded();
         }
     }