Fix dispatch of OnLayout event for first render

Summary: This diff ensures that Events delivered from the C++ side are actually processed. This is done forcing the execution of AsyncEventBeat.beat() in these cases

Reviewed By: shergin

Differential Revision: D13313955

fbshipit-source-id: b2785647913a640c2d557f4fa08d447845a540e9

Author: mdvacca

Diff for: ReactAndroid/src/main/java/com/facebook/react/uimanager/events/EventDispatcher.java

@@ -117,7 +117,7 @@ public void dispatchEvent(Event event) {
     for (EventDispatcherListener listener : mListeners) {
       listener.onEventDispatch(event);
     }
-    
+
     synchronized (mEventsStagingLock) {
       mEventStaging.add(event);
       Systrace.startAsyncFlow(
@@ -137,6 +137,10 @@ public void dispatchEvent(Event event) {
     }
   }
 
+  public void dispatchAllEvents() {
+    mCurrentFrameCallback.maybePostFromNonUI();
+  }
+
   /**
    * Add a listener to this EventDispatcher.
    */
@@ -286,7 +290,7 @@ public void doFrame(long frameTimeNanos) {
       try {
         moveStagedEventsToDispatchQueue();
 
-        if (mEventsToDispatchSize > 0 && !mHasDispatchScheduled) {
+        if (!mHasDispatchScheduled) {
           mHasDispatchScheduled = true;
           Systrace.startAsyncFlow(
               Systrace.TRACE_TAG_REACT_JAVA_BRIDGE,
@@ -347,26 +351,26 @@ public void run() {
         mHasDispatchScheduled = false;
         Assertions.assertNotNull(mReactEventEmitter);
         synchronized (mEventsToDispatchLock) {
-          // We avoid allocating an array and iterator, and "sorting" if we don't need to.
-          // This occurs when the size of mEventsToDispatch is zero or one.
-          if (mEventsToDispatchSize > 1) {
-            Arrays.sort(mEventsToDispatch, 0, mEventsToDispatchSize, EVENT_COMPARATOR);
-          }
-          for (int eventIdx = 0; eventIdx < mEventsToDispatchSize; eventIdx++) {
-            Event event = mEventsToDispatch[eventIdx];
-            // Event can be null if it has been coalesced into another event.
-            if (event == null) {
-              continue;
+          if (mEventsToDispatchSize > 0) {
+            // We avoid allocating an array and iterator, and "sorting" if we don't need to.
+            // This occurs when the size of mEventsToDispatch is zero or one.
+            if (mEventsToDispatchSize > 1) {
+              Arrays.sort(mEventsToDispatch, 0, mEventsToDispatchSize, EVENT_COMPARATOR);
+            }
+            for (int eventIdx = 0; eventIdx < mEventsToDispatchSize; eventIdx++) {
+              Event event = mEventsToDispatch[eventIdx];
+              // Event can be null if it has been coalesced into another event.
+              if (event == null) {
+                continue;
+              }
+              Systrace.endAsyncFlow(
+                  Systrace.TRACE_TAG_REACT_JAVA_BRIDGE, event.getEventName(), event.getUniqueID());
+              event.dispatch(mReactEventEmitter);
+              event.dispose();
             }
-            Systrace.endAsyncFlow(
-                Systrace.TRACE_TAG_REACT_JAVA_BRIDGE,
-                event.getEventName(),
-                event.getUniqueID());
-            event.dispatch(mReactEventEmitter);
-            event.dispose();
+            clearEventsToDispatch();
+            mEventCookieToLastEventIdx.clear();
           }
-          clearEventsToDispatch();
-          mEventCookieToLastEventIdx.clear();
         }
         for (BatchEventDispatchedListener listener : mPostEventDispatchListeners) {
           listener.onBatchEventDispatched();