Clear reference to the IIntentReceiver in order to avoid memory leak

When using sendOrderedBroadcast(..) with a BroadcastReceiver the
BroadcastReceiver instance was not released. The reason for this was that
the resultTo field in the BroadcastRecord kept a reference until it was pushed
out of the mBroadcastHistory. This reference in turn kept a reference to the
process side IIntentReceiver (implemented in ReceiverDispatcher$InnerReceiver).
This in turn had a strong reference (through mStrongRef) to the Context.

In order to keep the debug output the resultTo is also kept as a String in the
new resultToString variable.

Change-Id: I4382a22a541c27b3694fb2b78a04ee820b235f8f

2 files changed, 8 insertions, 3 deletions

diff --git a/services/java/com/android/server/am/ActivityManagerService.java b/services/java/com/android/server/am/ActivityManagerService.java
index 0aebc1c..837011e 100644
--- a/services/java/com/android/server/am/ActivityManagerService.java
+++ b/services/java/com/android/server/am/ActivityManagerService.java
@@ -13199,6 +13199,9 @@ public final class ActivityManagerService extends ActivityManagerNative implemen
                             performReceive(r.callerApp, r.resultTo,
                                 new Intent(r.intent), r.resultCode,
                                 r.resultData, r.resultExtras, false, false);
+                            // Set this to null so that the reference
+                            // (local and remote) isnt kept in the mBroadcastHistory.
+                            r.resultTo = null;
                         } catch (RemoteException e) {
                             Slog.w(TAG, "Failure sending broadcast result of " + r.intent, e);
                         }
diff --git a/services/java/com/android/server/am/BroadcastRecord.java b/services/java/com/android/server/am/BroadcastRecord.java
index c3f0b3e..4faaeca 100644
--- a/services/java/com/android/server/am/BroadcastRecord.java
+++ b/services/java/com/android/server/am/BroadcastRecord.java
@@ -44,7 +44,8 @@ class BroadcastRecord extends Binder {
     final boolean initialSticky; // initial broadcast from register to sticky?
     final String requiredPermission; // a permission the caller has required
     final List receivers;   // contains BroadcastFilter and ResolveInfo
-    final IIntentReceiver resultTo; // who receives final result if non-null
+    IIntentReceiver resultTo; // who receives final result if non-null
+    private final String resultToString; // resultTo.toString() used for debug purposes
     long dispatchTime;      // when dispatch started on this set of receivers
     long receiverTime;      // when current receiver started for timeouts.
     long finishTime;        // when we finished the broadcast.
@@ -100,8 +101,8 @@ class BroadcastRecord extends Binder {
         if (anrCount != 0) {
             pw.println(prefix + "anrCount=" + anrCount);
         }
-        if (resultTo != null || resultCode != -1 || resultData != null) {
-            pw.println(prefix + "resultTo=" + resultTo
+        if (resultToString != null || resultCode != -1 || resultData != null) {
+            pw.println(prefix + "resultTo=" + resultToString
                   + " resultCode=" + resultCode + " resultData=" + resultData);
         }
         if (resultExtras != null) {
@@ -164,6 +165,7 @@ class BroadcastRecord extends Binder {
         requiredPermission = _requiredPermission;
         receivers = _receivers;
         resultTo = _resultTo;
+        resultToString = resultTo == null ? null : resultTo.toString();
         resultCode = _resultCode;
         resultData = _resultData;
         resultExtras = _resultExtras;