[scheduler] Discard anomalously long tasks and bump metrics version.

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index 3ea78b99b6b12ddc35d6b4c01a7be89c01308b16..4872ae7e02a5c3adca0068197c4743421562bc6a 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -59036,6 +59036,10 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="RendererScheduler.BackgroundRendererMainThreadLoad" units="%">
+  <obsolete>
+    Replaced with RendererScheduler.BackgroundRendererMainThreadLoad2 as of May
+    2017.
+  </obsolete>
   <owner>altimin@chromium.org</owner>
   <summary>
     Renderer main thread load when renderer is backgrounded, i.e. percentage of
@@ -59047,6 +59051,21 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="RendererScheduler.BackgroundRendererMainThreadLoad2" units="%">
+  <owner>altimin@chromium.org</owner>
+  <summary>
+    Renderer main thread load when renderer is backgrounded, i.e. percentage of
+    time spent on running tasks.
+
+    This metric is emitted when the renderer main thread task is completed or
+    renderer is backgrounded or foregrounded, at most once per minute per
+    renderer amortized.
+
+    Note that this metric discards tasks longer than 30 seconds because they are
+    considered to be a result of measurement glitch.
+  </summary>
+</histogram>
+
 <histogram name="RendererScheduler.ExpectedTaskQueueingDuration" units="ms">
   <owner>tdresser@chromium.org</owner>
   <summary>
@@ -59057,6 +59076,10 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="RendererScheduler.ForegroundRendererMainThreadLoad" units="%">
+  <obsolete>
+    Replaced with RendererScheduler.ForegroundRendererMainThreadLoad2 as of May
+    2017.
+  </obsolete>
   <owner>altimin@chromium.org</owner>
   <summary>
     Renderer main thread load when renderer is foregrounded, i.e. percentage of
@@ -59068,18 +59091,52 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="RendererScheduler.ForegroundRendererMainThreadLoad2" units="%">
+  <owner>altimin@chromium.org</owner>
+  <summary>
+    Renderer main thread load when renderer is foregrounded, i.e. percentage of
+    time spent on running tasks.
+
+    This metric is emitted when the renderer main thread task is completed or
+    renderer is backgrounded or foregrounded, at most once per minute per
+    renderer amortized.
+
+    Note that this metric discards tasks longer than 30 seconds because they are
+    considered to be a result of measurement glitch.
+  </summary>
+</histogram>
+
 <histogram name="RendererScheduler.NumberOfTasksPerQueueType"
     enum="RendererSchedulerTaskQueueType">
+  <obsolete>
+    Replaced with RendererScheduler.NumberOfTasksPerQueueType2 as of May 2017.
+  </obsolete>
+  <owner>altimin@chromium.org,alexclarke@chromium.org</owner>
+  <summary>
+    The number of completed renderer tasks split per task queue type. Used to
+    monitor usage of each type of task queue. Reported each time when task is
+    completed.
+  </summary>
+</histogram>
+
+<histogram name="RendererScheduler.NumberOfTasksPerQueueType2"
+    enum="RendererSchedulerTaskQueueType">
   <owner>altimin@chromium.org,alexclarke@chromium.org</owner>
   <summary>
     The number of completed renderer tasks split per task queue type. Used to
     monitor usage of each type of task queue. Reported each time when task is
     completed.
+
+    Note that this metric discards tasks longer than 30 seconds because they are
+    considered to be a result of measurement glitch.
   </summary>
 </histogram>
 
 <histogram name="RendererScheduler.TaskDurationPerQueueType"
     enum="RendererSchedulerTaskQueueType" units="ms">
+  <obsolete>
+    Replaced with RendererScheduler.TaskDurationPerQueueType2 as of May 2017.
+  </obsolete>
   <owner>altimin@chromium.org,alexclarke@chromium.org</owner>
   <summary>
     Total duration of renderer tasks split per task queue type. Used to monitor
@@ -59091,6 +59148,22 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="RendererScheduler.TaskDurationPerQueueType2"
+    enum="RendererSchedulerTaskQueueType" units="ms">
+  <owner>altimin@chromium.org,alexclarke@chromium.org</owner>
+  <summary>
+    Total duration of renderer tasks split per task queue type. Used to monitor
+    usage of each type of task queues. Reported each time when task is completed
+    and current accumulated duration is longer than 1ms.
+
+    This metric is susceptible to problematic outliers and should be analyzed
+    with custom scripts accounting for that rather than from a dashboard.
+
+    Note that this metric discards tasks longer than 30 seconds because they are
+    considered to be a result of measurement glitch.
+  </summary>
+</histogram>
+
 <histogram name="RendererScheduler.TaskQueueManager.DelayedTaskLateness"
     units="ms">
   <owner>alexclarke@chromium.org</owner>
@@ -59113,11 +59186,26 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="RendererScheduler.TaskTime" units="microseconds">
+  <obsolete>
+    Replaced with RendererScheduler.TaskTime2 as of May 2017.
+  </obsolete>
+  <owner>sunyunjia@chromium.org</owner>
+  <owner>tdresser@chromium.org</owner>
+  <summary>
+    The duration of every task queued in the _renderer_ scheduler to see the
+    distribution of the task duration.
+  </summary>
+</histogram>
+
+<histogram name="RendererScheduler.TaskTime2" units="microseconds">
   <owner>sunyunjia@chromium.org</owner>
   <owner>tdresser@chromium.org</owner>
   <summary>
     The duration of every task queued in the _renderer_ scheduler to see the
     distribution of the task duration.
+
+    Note that this metric discards tasks longer than 30 seconds because they are
+    considered to be a result of measurement glitch.
   </summary>
 </histogram>