No missedFrame in case of no damage

If the reporter in the stage of beginImpl is replaced with a new
reporter, that means that Impl frame has caused no damage, and should
not be reported as MissedFrame.

Bug: chromium:1030304
Change-Id: I248a4dabf848e2ef6fc752c9388f60a6118092d4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1951651
Commit-Queue: Sadrul Chowdhury <sadrul@chromium.org>
Reviewed-by: Sadrul Chowdhury <sadrul@chromium.org>
Cr-Commit-Position: refs/heads/master@{#721874}

cc/metrics/compositor_frame_reporting_controller.cc

@@ -52,8 +52,10 @@ base::TimeTicks CompositorFrameReportingController::Now() const {
 void CompositorFrameReportingController::WillBeginImplFrame() {
   base::TimeTicks begin_time = Now();
   if (reporters_[PipelineStage::kBeginImplFrame]) {
+    // If the the reporter is replaced in this stage, it means that Impl frame
+    // caused no damage.
     reporters_[PipelineStage::kBeginImplFrame]->TerminateFrame(
-        CompositorFrameReporter::FrameTerminationStatus::kReplacedByNewReporter,
+        CompositorFrameReporter::FrameTerminationStatus::kDidNotProduceFrame,
         begin_time);
   }
   std::unique_ptr<CompositorFrameReporter> reporter =

cc/metrics/compositor_frame_reporting_controller_unittest.cc

@@ -230,6 +230,15 @@ TEST_F(CompositorFrameReportingControllerTest,
       "CompositorLatency.MissedFrame.EndActivateToSubmitCompositorFrame", 0);
 }
 
+TEST_F(CompositorFrameReportingControllerTest, ImplFrameCausedNoDamage) {
+  base::HistogramTester histogram_tester;
+
+  SimulateBeginImplFrame();
+  SimulateBeginImplFrame();
+  histogram_tester.ExpectTotalCount(
+      "CompositorLatency.MissedFrame.BeginImplFrameToSendBeginMainFrame", 0);
+}
+
 TEST_F(CompositorFrameReportingControllerTest, BlinkBreakdown) {
   base::HistogramTester histogram_tester;