Don't finish noHistory="true" activities behind the lock screen

The foreground activity is stopped when the device goes to sleep,
and started again when the device is unlocked.  We now distinguish
this case from a "normal" stop, and do not finish() a foreground
noHistory="true" activity inappropriately when the device sleeps.
We also detect the case where an activity is started while the
device is still asleep, in which case the foreground noHistory
activity is cleaned up as part of bringing the new activity to
the foreground.

Bug 6657549

Change-Id: I9c6a0830aed0e47e4207b62803b90067c8486112

Author: Christopher Tate

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

@@ -1474,6 +1474,21 @@ final boolean resumeTopActivityLocked(ActivityRecord prev, Bundle options) {
             return true;
         }
 
+        // If the most recent activity was noHistory but was only stopped rather
+        // than stopped+finished because the device went to sleep, we need to make
+        // sure to finish it as we're making a new activity topmost.
+        final ActivityRecord last = mLastPausedActivity;
+        if (mService.mSleeping && last != null && !last.finishing) {
+            if ((last.intent.getFlags()&Intent.FLAG_ACTIVITY_NO_HISTORY) != 0
+                    || (last.info.flags&ActivityInfo.FLAG_NO_HISTORY) != 0) {
+                if (DEBUG_STATES) {
+                    Slog.d(TAG, "no-history finish of " + last + " on new resume");
+                }
+                requestFinishActivityLocked(last.appToken, Activity.RESULT_CANCELED, null,
+                "no-history");
+            }
+        }
+
         if (prev != null && prev != next) {
             if (!prev.waitingVisible && next != null && !next.nowVisible) {
                 prev.waitingVisible = true;
@@ -3279,8 +3294,16 @@ private final void stopActivityLocked(ActivityRecord r) {
         if ((r.intent.getFlags()&Intent.FLAG_ACTIVITY_NO_HISTORY) != 0
                 || (r.info.flags&ActivityInfo.FLAG_NO_HISTORY) != 0) {
             if (!r.finishing) {
-                requestFinishActivityLocked(r.appToken, Activity.RESULT_CANCELED, null,
-                        "no-history");
+                if (!mService.mSleeping) {
+                    if (DEBUG_STATES) {
+                        Slog.d(TAG, "no-history finish of " + r);
+                    }
+                    requestFinishActivityLocked(r.appToken, Activity.RESULT_CANCELED, null,
+                            "no-history");
+                } else {
+                    if (DEBUG_STATES) Slog.d(TAG, "Not finishing noHistory " + r
+                            + " on stop because we're just sleeping");
+                }
             }
         }
 
@@ -3526,9 +3549,10 @@ final ActivityRecord activityIdleInternal(IBinder token, boolean fromTimeout,
     final boolean requestFinishActivityLocked(IBinder token, int resultCode,
             Intent resultData, String reason) {
         int index = indexOfTokenLocked(token);
-        if (DEBUG_RESULTS) Slog.v(
+        if (DEBUG_RESULTS || DEBUG_STATES) Slog.v(
                 TAG, "Finishing activity @" + index + ": token=" + token
-                + ", result=" + resultCode + ", data=" + resultData);
+                + ", result=" + resultCode + ", data=" + resultData
+                + ", reason=" + reason);
         if (index < 0) {
             return false;
         }