cc: Remove retro frames from scheduler.

cc/test/fake_external_begin_frame_source.cc

Index: cc/test/fake_external_begin_frame_source.cc
diff --git a/cc/test/fake_external_begin_frame_source.cc b/cc/test/fake_external_begin_frame_source.cc
index fee842b25604166fa94a9aceaa35c46cf62dda67..a1ef1f2a6da1de6a7099fe17484adada5a6b995f 100644
--- a/cc/test/fake_external_begin_frame_source.cc
+++ b/cc/test/fake_external_begin_frame_source.cc
@@ -22,6 +22,18 @@ FakeExternalBeginFrameSource::~FakeExternalBeginFrameSource() {
   DCHECK(CalledOnValidThread());
 }
 
+void FakeExternalBeginFrameSource::DidFinishFrame(BeginFrameObserver* obs) {
+  DCHECK(CalledOnValidThread());
+  // Send a MISSED begin frame if necessary.
+  if (missed_begin_frame_args_.IsValid()) {
+    BeginFrameArgs last_args = obs->LastUsedBeginFrameArgs();
+    if (!last_args.IsValid() ||
+        (missed_begin_frame_args_.frame_time > last_args.frame_time)) {
+      obs->OnBeginFrame(missed_begin_frame_args_);
+    }
+  }
+}
+
 void FakeExternalBeginFrameSource::OnNeedsBeginFramesChanged(
     bool needs_begin_frames) {
   DCHECK(CalledOnValidThread());
@@ -34,7 +46,10 @@ void FakeExternalBeginFrameSource::OnNeedsBeginFramesChanged(
 
 void FakeExternalBeginFrameSource::TestOnBeginFrame() {
   DCHECK(CalledOnValidThread());
-  CallOnBeginFrame(CreateBeginFrameArgsForTesting(BEGINFRAME_FROM_HERE));
+  BeginFrameArgs args = CreateBeginFrameArgsForTesting(BEGINFRAME_FROM_HERE);
+  missed_begin_frame_args_ = args;
+  missed_begin_frame_args_.type = BeginFrameArgs::MISSED;
+  CallOnBeginFrame(args);
   PostTestOnBeginFrame();
 }