Don't wait for current activity to pause before resuming next.

We can do this now that we ensure processes are not killed until
they have been stopped.  If the two activities are in the same
process, the ordering will still be correct because we schedule
the pause before the resume.

Change-Id: I209ba739b41e832d35db3edd34d1e7af354cc183

Author: Dianne Hackborn

services/java/com/android/server/am/ActivityManagerService.java

@@ -138,6 +138,7 @@
 import java.lang.IllegalStateException;
 import java.lang.ref.WeakReference;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.Comparator;
@@ -3520,13 +3521,7 @@ private final void handleAppDiedLocked(ProcessRecord app,
         }
 
         // Just in case...
-        if (mMainStack.mPausingActivity != null && mMainStack.mPausingActivity.app == app) {
-            if (DEBUG_PAUSE) Slog.v(TAG, "App died while pausing: " +mMainStack.mPausingActivity);
-            mMainStack.mPausingActivity = null;
-        }
-        if (mMainStack.mLastPausedActivity != null && mMainStack.mLastPausedActivity.app == app) {
-            mMainStack.mLastPausedActivity = null;
-        }
+        mMainStack.appDiedLocked(app);
 
         // Remove this application's activities from active lists.
         mMainStack.removeHistoryRecordsForAppLocked(app);
@@ -7231,7 +7226,7 @@ public boolean shutdown(int timeout) {
                 mMainStack.stopIfSleepingLocked();
                 final long endTime = System.currentTimeMillis() + timeout;
                 while (mMainStack.mResumedActivity != null
-                        || mMainStack.mPausingActivity != null) {
+                        || mMainStack.mPausingActivities.size() > 0) {
                     long delay = endTime - System.currentTimeMillis();
                     if (delay <= 0) {
                         Slog.w(TAG, "Activity manager shutdown timed out");
@@ -9025,8 +9020,13 @@ boolean dumpActivitiesLocked(FileDescriptor fd, PrintWriter pw, String[] args,
         }
 
         pw.println(" ");
-        if (mMainStack.mPausingActivity != null) {
-            pw.println("  mPausingActivity: " + mMainStack.mPausingActivity);
+        if (mMainStack.mPausingActivities.size() > 0) {
+            pw.println("  mPausingActivities: " + Arrays.toString(
+                    mMainStack.mPausingActivities.toArray()));
+        }
+        if (mMainStack.mInputPausedActivities.size() > 0) {
+            pw.println("  mInputPausedActivities: " + Arrays.toString(
+                    mMainStack.mInputPausedActivities.toArray()));
         }
         pw.println("  mResumedActivity: " + mMainStack.mResumedActivity);
         pw.println("  mFocusedActivity: " + mFocusedActivity);
@@ -14759,7 +14759,13 @@ private final boolean updateOomAdjLocked(
     private final ActivityRecord resumedAppLocked() {
         ActivityRecord resumedActivity = mMainStack.mResumedActivity;
         if (resumedActivity == null || resumedActivity.app == null) {
-            resumedActivity = mMainStack.mPausingActivity;
+            for (int i=mMainStack.mPausingActivities.size()-1; i>=0; i--) {
+                ActivityRecord r = mMainStack.mPausingActivities.get(i);
+                if (r.app != null) {
+                    resumedActivity = r;
+                    break;
+                }
+            }
             if (resumedActivity == null || resumedActivity.app == null) {
                 resumedActivity = mMainStack.topRunningActivityLocked(null);
             }

services/java/com/android/server/am/ActivityRecord.java

@@ -602,6 +602,7 @@ public void stopFreezingScreenLocked(boolean force) {
 
     public void windowsDrawn() {
         synchronized(service) {
+            stack.reportActivityDrawnLocked(this);
             if (launchTime != 0) {
                 final long curTime = SystemClock.uptimeMillis();
                 final long thisTime = curTime - launchTime;
@@ -690,7 +691,9 @@ private ActivityRecord getWaitingHistoryRecordLocked() {
             // Hmmm, who might we be waiting for?
             r = stack.mResumedActivity;
             if (r == null) {
-                r = stack.mPausingActivity;
+                if (stack.mPausingActivities.size() > 0) {
+                    r = stack.mPausingActivities.get(stack.mPausingActivities.size()-1);
+                }
             }
             // Both of those null?  Fall back to 'this' again
             if (r == null) {