Bag of scheduling tweaks

 Bug: 15118640

 * Prevent over-stuffing the queue by dropping frames
 * Prevent double-drawing in one pulse by RT by deferring
   vsync registration until post-draw so that it catches
   the next vsync pulse instead of the current one
 * Bias vsync race condition towards the UI thread
 * Fix queueDelay to actually work

Change-Id: Ibf584258bd93ebcbba058bd976dc8b307f1c6155
diff --git a/libs/hwui/renderthread/RenderProxy.h b/libs/hwui/renderthread/RenderProxy.h
index 4d3499e..8aeb264 100644
--- a/libs/hwui/renderthread/RenderProxy.h
+++ b/libs/hwui/renderthread/RenderProxy.h
@@ -82,6 +82,7 @@
     ANDROID_API void destroyLayer(DeferredLayerUpdater* layer);
 
     ANDROID_API void fence();
+    ANDROID_API void notifyFramePending();
 
 private:
     RenderThread& mRenderThread;