Merge 114475 - [chromium] Ensure RateLimiter waits for Swapbuffers completion

Source/WebCore/platform/graphics/chromium/cc/CCLayerTreeHost.cpp

Index: Source/WebCore/platform/graphics/chromium/cc/CCLayerTreeHost.cpp
===================================================================
--- Source/WebCore/platform/graphics/chromium/cc/CCLayerTreeHost.cpp	(revision 114962)
+++ Source/WebCore/platform/graphics/chromium/cc/CCLayerTreeHost.cpp	(working copy)
@@ -634,12 +634,19 @@
     if (it != m_rateLimiters.end())
         it->second->start();
     else {
-        RefPtr<RateLimiter> rateLimiter = RateLimiter::create(context);
+        RefPtr<RateLimiter> rateLimiter = RateLimiter::create(context, this);
         m_rateLimiters.set(context, rateLimiter);
         rateLimiter->start();
     }
 }
 
+void CCLayerTreeHost::rateLimit()
+{
+    // Force a no-op command on the compositor context, so that any ratelimiting commands will wait for the compositing
+    // context, and therefore for the SwapBuffers.
+    m_proxy->forceSerializeOnSwapBuffers();
+}
+
 void CCLayerTreeHost::stopRateLimiter(GraphicsContext3D* context)
 {
     RateLimiterMap::iterator it = m_rateLimiters.find(context);