Bug 740883 - Coalesce VIEWPORT events across NATIVE_POKE and DRAW events on insertion. r=Cwiiis

widget/android/nsAppShell.cpp

@@ -517,6 +517,11 @@ void
 nsAppShell::PostEvent(AndroidGeckoEvent *ae)
 {
     {
+        // set this to true when inserting events that we can coalesce
+        // viewport events across. this is effectively maintaining a whitelist
+        // of events that are unaffected by viewport changes.
+        bool allowCoalescingNextViewport = false;
+
         MutexAutoLock lock(mQueueLock);
         EVLOG("nsAppShell::PostEvent %p %d", ae, ae->Type());
         switch (ae->Type()) {
@@ -586,6 +591,9 @@ nsAppShell::PostEvent(AndroidGeckoEvent *ae)
             } else {
                 mQueuedDrawEvent = ae;
             }
+
+            allowCoalescingNextViewport = true;
+
             mEventQueue.AppendElement(ae);
             break;
 
@@ -600,6 +608,7 @@ nsAppShell::PostEvent(AndroidGeckoEvent *ae)
             // temporarily turn off draw-coalescing, so that we process a draw
             // event as soon as possible after a viewport change
             mAllowCoalescingNextDraw = false;
+            allowCoalescingNextViewport = true;
 
             mEventQueue.AppendElement(ae);
             break;
@@ -620,10 +629,20 @@ nsAppShell::PostEvent(AndroidGeckoEvent *ae)
             mEventQueue.AppendElement(ae);
             break;
 
+        case AndroidGeckoEvent::NATIVE_POKE:
+            allowCoalescingNextViewport = true;
+            // fall through
+
         default:
             mEventQueue.AppendElement(ae);
             break;
         }
+
+        // if the event wasn't on our whitelist then reset mQueuedViewportEvent
+        // so that we don't coalesce future viewport events into the last viewport
+        // event we added
+        if (!allowCoalescingNextViewport)
+            mQueuedViewportEvent = nsnull;
     }
     NotifyNativeEvent();
 }