Deflake pixel tests on android webview

Issue is sometimes synchronous compositor can drop
PresentationFeedback if renderer did not request a begin frame.
Fix this by always supplying the PresentationFeedback.

Bug: 948114
Change-Id: I75275eee17e03704dfff4406c141c68299af3ae6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1546875
Commit-Queue: Bo <boliu@chromium.org>
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#647118}

content/renderer/android/synchronous_compositor_proxy.cc

@@ -294,8 +294,11 @@ void SynchronousCompositorProxy::BeginFrame(
     needs_begin_frame_for_animate_input_ = false;
     input_handler_proxy_->SynchronouslyAnimate(args.frame_time);
   }
-  if (needs_begin_frame_for_frame_sink_ && layer_tree_frame_sink_)
-    layer_tree_frame_sink_->BeginFrame(args, presentation_feedbacks);
+  if (layer_tree_frame_sink_) {
+    layer_tree_frame_sink_->DidPresentCompositorFrame(presentation_feedbacks);
+    if (needs_begin_frame_for_frame_sink_)
+      layer_tree_frame_sink_->BeginFrame(args);
+  }
 
   SyncCompositorCommonRendererParams param;
   PopulateCommonParams(&param);

content/renderer/android/synchronous_layer_tree_frame_sink.cc

@@ -543,14 +543,17 @@ void SynchronousLayerTreeFrameSink::OnNeedsBeginFrames(
   }
 }
 
-void SynchronousLayerTreeFrameSink::BeginFrame(
-    const viz::BeginFrameArgs& args,
+void SynchronousLayerTreeFrameSink::DidPresentCompositorFrame(
     const viz::PresentationFeedbackMap& presentation_feedbacks) {
-  if (client_) {
-    for (const auto& pair : presentation_feedbacks) {
-      client_->DidPresentCompositorFrame(pair.first, pair.second);
-    }
+  if (!client_)
+    return;
+  for (const auto& pair : presentation_feedbacks) {
+    client_->DidPresentCompositorFrame(pair.first, pair.second);
   }
+}
+
+void SynchronousLayerTreeFrameSink::BeginFrame(
+    const viz::BeginFrameArgs& args) {
   if (external_begin_frame_source_)
     external_begin_frame_source_->OnBeginFrame(args);
 }

content/renderer/android/synchronous_layer_tree_frame_sink.h

@@ -122,8 +122,9 @@ class SynchronousLayerTreeFrameSink
   // viz::ExternalBeginFrameSourceClient overrides.
   void OnNeedsBeginFrames(bool needs_begin_frames) override;
 
-  void BeginFrame(const viz::BeginFrameArgs& args,
-                  const viz::PresentationFeedbackMap& presentation_feedbacks);
+  void DidPresentCompositorFrame(
+      const viz::PresentationFeedbackMap& presentation_feedbacks);
+  void BeginFrame(const viz::BeginFrameArgs& args);
   void SetBeginFrameSourcePaused(bool paused);
   void SetMemoryPolicy(size_t bytes_limit);
   void ReclaimResources(uint32_t layer_tree_frame_sink_id,