[cc/metrics] More trace fixes.

It is possible to start new stages after a frame has been marked
as 'did not produce frame'. Sometimes these reports can go on and
produce frames (e.g. if the main-thread comes back late after the
deadline). However, in other times, the reporters can terminate as
'did not produce frame'. For such frames, do not report the stages
that started after the initial 'did not produce' notification.

BUG=1074567
TBR=behdadb@chromium.org

Change-Id: I4d45372d8a973247fb129c0964776179d9f009e9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2167174Reviewed-by: Sadrul Chowdhury <sadrul@chromium.org>
Commit-Queue: Sadrul Chowdhury <sadrul@chromium.org>
Auto-Submit: Sadrul Chowdhury <sadrul@chromium.org>
Cr-Commit-Position: refs/heads/master@{#762699}

cc/metrics/compositor_frame_reporter.cc

@@ -670,6 +670,11 @@ void CompositorFrameReporter::ReportAllTraceEvents(
       const int stage_type_index = static_cast<int>(stage.stage_type);
       CHECK_LT(stage_type_index, static_cast<int>(StageType::kStageTypeCount));
       CHECK_GE(stage_type_index, 0);
+      if (stage.start_time >= frame_termination_time_)
+        break;
+      DCHECK_GE(stage.end_time, stage.start_time);
+      if (stage.start_time == stage.end_time)
+        continue;
       const char* name = GetStageName(stage_type_index);
       TRACE_EVENT_NESTABLE_ASYNC_BEGIN_WITH_TIMESTAMP0(
           "cc,benchmark", name, trace_id, stage.start_time);
@@ -711,10 +716,9 @@ void CompositorFrameReporter::ReportAllTraceEvents(
       TestReportType(FrameReportType::kDroppedFrame) ? "dropped_frame"
                                                      : "non_dropped_frame";
   TRACE_EVENT_NESTABLE_ASYNC_END_WITH_TIMESTAMP2(
-      "cc,benchmark", "PipelineReporter", trace_id,
-      stage_history_.back().end_time, "termination_status",
-      termination_status_str, "compositor_frame_submission_status",
-      submission_status_str);
+      "cc,benchmark", "PipelineReporter", trace_id, frame_termination_time_,
+      "termination_status", termination_status_str,
+      "compositor_frame_submission_status", submission_status_str);
 }
 
 base::TimeDelta CompositorFrameReporter::SumOfStageHistory() const {