Fix multiple configuration changes in multiwindow

When in split-screen mode and activity handles configuration changes
it gets 2 onConfigurationChanged calls which originate from
ActivityManagerService#updateConfigurationLocked:
1. app.thread.scheduleConfigurationChanged calls to all process records
   send configuration of the whole screen for corresponding orientation,
   which leads to CONFIGURATION_CHANGED message in ActivityThread.
2. mStackSupervisor.resizeStackLocked call resizes both visible stacks and
   eventually ActivityThread receives ACTIVITY_CONFIGURATION_CHANGED
   message with correct configuration corresponding to space occupied in
   split-screen.

In this CL if component callback is an instance of Activity and it had
override config set - onConfigurationChanged will not be triggered unless
override config has changed.

Bug: 27948331
Change-Id: Ia73b045570b44eb5b351811bf6c4f63d78c3f909
diff --git a/core/java/android/app/ActivityThread.java b/core/java/android/app/ActivityThread.java
index 96e1eaa..36e962e 100644
--- a/core/java/android/app/ActivityThread.java
+++ b/core/java/android/app/ActivityThread.java
@@ -4727,8 +4727,16 @@
         if (callbacks != null) {
             final int N = callbacks.size();
             for (int i=0; i<N; i++) {
-                performConfigurationChanged(callbacks.get(i), null, config, null,
-                        REPORT_TO_ACTIVITY);
+                ComponentCallbacks2 cb = callbacks.get(i);
+                if (cb instanceof Activity) {
+                    // If callback is an Activity - call corresponding method to consider override
+                    // config and avoid onConfigurationChanged if it hasn't changed.
+                    Activity a = (Activity) cb;
+                    performConfigurationChangedForActivity(mActivities.get(a.getActivityToken()),
+                            config, REPORT_TO_ACTIVITY);
+                } else {
+                    performConfigurationChanged(cb, null, config, null, REPORT_TO_ACTIVITY);
+                }
             }
         }
     }