Deliver IPC messages together with SwapCompositorFrame

content/renderer/gpu/render_widget_compositor.cc

Index: content/renderer/gpu/render_widget_compositor.cc
diff --git a/content/renderer/gpu/render_widget_compositor.cc b/content/renderer/gpu/render_widget_compositor.cc
index f974828d94a1916a305bc8849e147573a6c1fd56..48653e909986f254f5242b1f6243bf56feb43874 100644
--- a/content/renderer/gpu/render_widget_compositor.cc
+++ b/content/renderer/gpu/render_widget_compositor.cc
@@ -19,6 +19,7 @@
 #include "base/values.h"
 #include "cc/base/latency_info_swap_promise.h"
 #include "cc/base/latency_info_swap_promise_monitor.h"
+#include "cc/base/swap_promise.h"
 #include "cc/base/switches.h"
 #include "cc/debug/layer_tree_debug_state.h"
 #include "cc/debug/micro_benchmark.h"
@@ -405,6 +406,10 @@ int RenderWidgetCompositor::GetLayerTreeId() const {
   return layer_tree_host_->id();
 }
 
+int RenderWidgetCompositor::GetSourceFrameNumber() const {
+  return layer_tree_host_->source_frame_number();
+}
+
 void RenderWidgetCompositor::NotifyInputThrottledUntilCommit() {
   layer_tree_host_->NotifyInputThrottledUntilCommit();
 }