viz: Report how far ahead invalid presentation timestamps are.

On android, it turns out the presentation timestamp coming from the
driver can be from the future. Report how far ahead in the future
these timestamps are.

BUG=894440

Change-Id: Ic9bf5620721de3279e8b74277273e8db63da0842
Reviewed-on: https://chromium-review.googlesource.com/c/1294193
Commit-Queue: Sadrul Chowdhury <sadrul@chromium.org>
Reviewed-by: Antoine Labour <piman@chromium.org>
Reviewed-by: Mark Pearson <mpearson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#601737}

components/viz/service/display/display.cc

@@ -526,7 +526,14 @@ void Display::DidReceivePresentationFeedback(
   const auto swap_time = pending_presented_callbacks_.front().first;
   DCHECK(!swap_time.is_null());
   if (!feedback.timestamp.is_null()) {
-    if (feedback.timestamp > base::TimeTicks::Now()) {
+    const auto now = base::TimeTicks::Now();
+    if (feedback.timestamp > now) {
+      const auto diff = feedback.timestamp - now;
+      // This collects the time-delta in buckets from 10ms up-to 3minutes. This
+      // should provide sufficient information about the spread.
+      // https://crbug.com/894440
+      UMA_HISTOGRAM_MEDIUM_TIMES(
+          "Graphics.PresentationTimestamp.InvalidFromFuture", diff);
       base::debug::DumpWithoutCrashing();
       // In debug builds, just crash immediately.
       DCHECK(false);

tools/metrics/histograms/histograms.xml

@@ -36378,6 +36378,18 @@ uploading your change for review.
   </summary>
 </histogram>
 
+<histogram name="Graphics.PresentationTimestamp.InvalidFromFuture" units="ms"
+    expires_after="2019-01-31">
+  <owner>sadrul@chromium.org</owner>
+  <summary>
+    Presentation timestamp comes from the driver when showing a display frame on
+    screen. These timestamps can sometimes be in the future. This metric records
+    how far in the future these timestamps can be. If the timestamp is not in
+    the future, then this metric is not recorded. This metric is recorded only
+    on Android.
+  </summary>
+</histogram>
+
 <histogram name="GraphicsPipeline.ReceivedBeginFrame" units="microseconds">
   <owner>yiyix@chromium.org</owner>
   <owner>chrome-gpu-metrics@google.com</owner>