[cc] Don't send missed BeginFrames with past deadline.

content/browser/renderer_host/render_widget_host_view_android.cc

Index: content/browser/renderer_host/render_widget_host_view_android.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_android.cc b/content/browser/renderer_host/render_widget_host_view_android.cc
index 51658bd97e183299957fffad8d66b27452d4f7e5..8573ddf067ca0b0d92d57edc62ada054fc4b6836 100644
--- a/content/browser/renderer_host/render_widget_host_view_android.cc
+++ b/content/browser/renderer_host/render_widget_host_view_android.cc
@@ -1556,16 +1556,12 @@ void RenderWidgetHostViewAndroid::StopObservingRootWindow() {
   DCHECK(!begin_frame_source_);
 }
 
-void RenderWidgetHostViewAndroid::SendBeginFrame(cc::BeginFrameArgs args) {
+void RenderWidgetHostViewAndroid::SendBeginFrame(
+    const cc::BeginFrameArgs& args) {
   TRACE_EVENT2("cc", "RenderWidgetHostViewAndroid::SendBeginFrame",
                "frame_number", args.sequence_number, "frame_time_us",
                args.frame_time.ToInternalValue());
 
-  // Synchronous compositor does not use deadline-based scheduling.
-  // TODO(brianderson): Replace this hardcoded deadline after Android
-  // switches to Surfaces and the Browser's commit isn't in the critical path.
-  args.deadline = sync_compositor_ ? base::TimeTicks()
-  : args.frame_time + (args.interval * 0.6);
   host_->Send(new ViewMsg_BeginFrame(host_->GetRoutingID(), args));
   if (sync_compositor_)
     sync_compositor_->DidSendBeginFrame(view_.GetWindowAndroid());
@@ -1993,6 +1989,7 @@ void RenderWidgetHostViewAndroid::OnDetachCompositor() {
 }
 
 void RenderWidgetHostViewAndroid::OnBeginFrame(const cc::BeginFrameArgs& args) {
+  // TODO(eseckler): Acknowledge BeginFrames.
   TRACE_EVENT0("cc,benchmark", "RenderWidgetHostViewAndroid::OnBeginFrame");
   if (!host_)
     return;
@@ -2003,6 +2000,23 @@ void RenderWidgetHostViewAndroid::OnBeginFrame(const cc::BeginFrameArgs& args) {
   if (sync_compositor_ && args.type == cc::BeginFrameArgs::MISSED)
     return;
 
+  cc::BeginFrameArgs adjusted_args = args;
+
+  if (sync_compositor_) {
+    // Synchronous compositor does not use deadline-based scheduling.
+    adjusted_args.deadline = base::TimeTicks();
+  } else {
+    // TODO(brianderson): Replace this hardcoded deadline after Android
+    // switches to Surfaces and the Browser's commit isn't in the critical path.
+    adjusted_args.deadline =
+        adjusted_args.frame_time + (adjusted_args.interval * 0.6);
+    // Avoid unnecessary IPC round trips of missed args with past deadline.
+    if (adjusted_args.type == cc::BeginFrameArgs::MISSED &&
+        base::TimeTicks::Now() > adjusted_args.deadline) {

[brianderson, 2017/03/24 19:57:28]

This will call Now() once per RWHV. Not a big deal on Android, but if this is a
pattern we're going to repeat elsewhere, should we pass in now as an argument to
OnBeginFrame?

Looking at other BeginFrameObservers, they don't always use Now(), so probably
not.

[Eric Seckler, 2017/03/27 09:53:25]

Yeay, the only reason we need it on android is the deadline adjustment above. No
other RWHVs do that. I think that's also the reason why we see "past-deadline"
missed BeginFrames in the renderer primarily on android.

+      return;
+    }
+  }
+
   // Update |last_begin_frame_args_| before handling
   // |outstanding_begin_frame_requests_| to prevent the BeginFrameSource from
   // sending the same MISSED args in infinite recursion. This may otherwise
@@ -2020,7 +2034,7 @@ void RenderWidgetHostViewAndroid::OnBeginFrame(const cc::BeginFrameArgs& args) {
   if ((outstanding_begin_frame_requests_ & BEGIN_FRAME) ||
       (outstanding_begin_frame_requests_ & PERSISTENT_BEGIN_FRAME)) {
     ClearBeginFrameRequest(BEGIN_FRAME);
-    SendBeginFrame(args);
+    SendBeginFrame(adjusted_args);
   }
 }