[cc/metrics] Fix trace-event for reporters that don't produce a frame.

If a reporter is replaced by a new reporter, but the frame had not
produced a frame, then use the timestamp of the 'did not produce'
notification as the termination-time to end the trace-event, rather than
the time of the replacement.

BUG=none

Change-Id: I91ad6b9a1b0c31afe5309f89e7f8aaf43121e8eb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2146517
Commit-Queue: Behdad Bakhshinategh <behdadb@chromium.org>
Reviewed-by: Behdad Bakhshinategh <behdadb@chromium.org>
Auto-Submit: Sadrul Chowdhury <sadrul@chromium.org>
Cr-Commit-Position: refs/heads/master@{#758867}

cc/metrics/compositor_frame_reporter.cc

@@ -290,7 +290,7 @@ void CompositorFrameReporter::OnAbortBeginMainFrame(base::TimeTicks timestamp) {
 }
 
 void CompositorFrameReporter::OnDidNotProduceFrame() {
-  did_not_produce_frame_ = true;
+  did_not_produce_frame_time_ = base::TimeTicks::Now();
 }
 
 void CompositorFrameReporter::SetBlinkBreakdown(

cc/metrics/compositor_frame_reporter.h

@@ -152,11 +152,17 @@ class CC_EXPORT CompositorFrameReporter {
   void OnAbortBeginMainFrame(base::TimeTicks timestamp);
   void OnDidNotProduceFrame();
   bool did_finish_impl_frame() const { return did_finish_impl_frame_; }
-  bool did_not_produce_frame() const { return did_not_produce_frame_; }
   base::TimeTicks impl_frame_finish_time() const {
     return impl_frame_finish_time_;
   }
 
+  bool did_not_produce_frame() const {
+    return did_not_produce_frame_time_.has_value();
+  }
+  base::TimeTicks did_not_produce_frame_time() const {
+    return *did_not_produce_frame_time_;
+  }
+
   bool did_abort_main_frame() const {
     return main_frame_abort_time_.has_value();
   }
@@ -236,13 +242,14 @@ class CC_EXPORT CompositorFrameReporter {
 
   // Indicates if work on Impl frame is finished.
   bool did_finish_impl_frame_ = false;
-  // Flag indicating if DidNotProduceFrame is called for this reporter
-  bool did_not_produce_frame_ = false;
   // The time that work on Impl frame is finished. It's only valid if the
   // reporter is in a stage other than begin impl frame.
   base::TimeTicks impl_frame_finish_time_;
   base::TimeTicks frame_deadline_;
 
+  // The timestamp of when the frame was marked as not having produced a frame
+  // (through a call to DidNotProduceFrame()).
+  base::Optional<base::TimeTicks> did_not_produce_frame_time_;
   base::Optional<base::TimeTicks> main_frame_abort_time_;
 };
 }  // namespace cc

cc/metrics/compositor_frame_reporting_controller.cc

@@ -319,16 +319,18 @@ void CompositorFrameReportingController::AdvanceReporterStage(
     PipelineStage target) {
   auto& reporter = reporters_[target];
   if (reporter) {
-    auto termination_time = (target == PipelineStage::kBeginMainFrame &&
-                             reporter->did_abort_main_frame())
-                                ? reporter->main_frame_abort_time()
-                                : Now();
-    if (reporters_[target]->did_not_produce_frame())
-      reporters_[target]->TerminateFrame(
-          FrameTerminationStatus::kDidNotProduceFrame, termination_time);
-    else
-      reporters_[target]->TerminateFrame(
-          FrameTerminationStatus::kReplacedByNewReporter, termination_time);
+    auto termination_status = FrameTerminationStatus::kReplacedByNewReporter;
+    base::TimeTicks termination_time;
+    if (reporter->did_not_produce_frame()) {
+      termination_time = reporter->did_not_produce_frame_time();
+      termination_status = FrameTerminationStatus::kDidNotProduceFrame;
+    } else if (target == PipelineStage::kBeginMainFrame &&
+               reporter->did_abort_main_frame()) {
+      termination_time = reporter->main_frame_abort_time();
+    } else {
+      termination_time = Now();
+    }
+    reporter->TerminateFrame(termination_status, termination_time);
   }
   reporters_[target] = std::move(reporters_[start]);
 }