Bug 1213762 - Clear AsyncCompositionManager::mIsFirstPaint on non-Android platforms, too. r=mstange

--HG--
extra : rebase_source : 86e4c9b185c9d5a0b57cc12099326008a5b08a55
extra : source : 84dbb629686454ce74c7cdf1ea18866f703a0b4d

gfx/layers/composite/AsyncCompositionManager.cpp

@@ -817,6 +817,10 @@ AsyncCompositionManager::ApplyAsyncContentTransformToTree(Layer *aLayer,
         mPaintSyncId = 0;
       }
     }
+#else
+    // Non-Android platforms still care about this flag being cleared after
+    // the first call to TransformShadowTree().
+    mIsFirstPaint = false;
 #endif
 
     // Transform the current local clip by this APZC's async transform. If we're