Track performance of toBlob and its complete timeout delay

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 28d90ca0cba04971f8185933e98c46b9baf60fd6..99a4e7dadabdda6da212b89d2ed655b4a2e7f9ef 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -3478,6 +3478,16 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <summary>Time spent on 2D canvas putImageData API call.</summary>
 </histogram>
 
+<histogram name="Blink.Canvas.ToBlob" units="microseconds">
+  <owner>junov@chromium.org</owner>

[Justin Novosad, 2016/06/07 21:43:44]

You can put more that one owner, you know? Please put xlai and myself on all of
these histograms.

+  <summary>Time spent on 2D canvas toBlob API call.</summary>
+</histogram>
+
+<histogram name="Blink.Canvas.ToBlobTimeoutDuration" units="microseconds">
+  <owner>xlai@chromium.org</owner>
+  <summary>Duration of a timeout event in a canvas.toBlob API call.</summary>
+</histogram>
+
 <histogram name="Blink.Canvas.ToDataURL" units="microseconds">
   <owner>junov@chromium.org</owner>
   <summary>Time spent on 2D canvas toDataURL API call.</summary>
@@ -4336,6 +4346,14 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Canvas.ToBlob.IdleTaskTimeout" enum="IdleTaskTimeoutType">
+  <owner>xlai@chromium.org</owner>
+  <summary>
+    Records the occurence of start/complete time out delay in canvas toBlob
+    calls.
+  </summary>
+</histogram>
+
 <histogram name="CAPSUpdater.Step" enum="CAPSUpdaterStep">
   <owner>cpu@chromium.org</owner>
   <summary>
@@ -76907,6 +76925,11 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </int>
 </enum>
 
+<enum name="IdleTaskTimeoutType" type="int">
+  <int value="0" label="IdleTaskStartTimeout"/>
+  <int value="2" label="IdleTaskCompleteTimeout"/>
+</enum>
+
 <enum name="IMECommitType" type="int">
   <obsolete>
     Deprecated 03/2015, and replaced by IMECommitType2.
@@ -91876,6 +91899,40 @@ To add a new entry, add it with any value and run test to compute valid value.
   <affected-histogram name="Blink.Canvas.PutImageData"/>
 </histogram_suffixes>
 
+<histogram_suffixes name="BlinkCanvasToBlobDuration" separator=".">
+  <affected-histogram name="Blink.Canvas.ToBlob.JPEG"/>
+  <suffix name="Succeed"/>
+  <suffix name="Failed"/>
+  <affected-histogram name="Blink.Canvas.ToBlob.PNG"/>
+  <affected-histogram name="Blink.Canvas.ToBlob.Unknown"/>
+  <affected-histogram name="Blink.Canvas.ToBlob.WEBP"/>
+</histogram_suffixes>
+
+<histogram_suffixes name="BlinkCanvasToBlobTimeoutTimer" separator=".">
+  <suffix name="Start"/>
+  <suffix name="Complete"/>
+  <affected-histogram name="Blink.Canvas.ToBlobTimeoutDuration.JPEG"/>
+  <affected-histogram name="Blink.Canvas.ToBlobTimeoutDuration.PNG"/>
+  <affected-histogram name="Blink.Canvas.ToBlobTimeoutDuration.Unknown"/>
+  <affected-histogram name="Blink.Canvas.ToBlobTimeoutDuration.WEBP"/>
+</histogram_suffixes>
+
+<histogram_suffixes name="BlinkCanvasToBlobTimeoutType" separator=".">
+  <suffix name="JPEG"/>
+  <suffix name="PNG"/>
+  <suffix name="Unknown"/>
+  <suffix name="WEBP"/>
+  <affected-histogram name="Blink.Canvas.ToBlobTimeoutDuration"/>
+</histogram_suffixes>
+
+<histogram_suffixes name="BlinkCanvasToBlobType" separator=".">
+  <suffix name="JPEG"/>
+  <suffix name="PNG"/>
+  <suffix name="Unknown"/>
+  <suffix name="WEBP"/>
+  <affected-histogram name="Blink.Canvas.ToBlob"/>
+</histogram_suffixes>
+
 <histogram_suffixes name="BlinkCanvasToDataURLTime" separator=".">
   <suffix name="BMP"/>
   <suffix name="GIF"/>
@@ -92088,6 +92145,14 @@ To add a new entry, add it with any value and run test to compute valid value.
   <affected-histogram name="Canvas.RequestedImageMimeTypes"/>
 </histogram_suffixes>
 
+<histogram_suffixes name="CanvasToBlobIdleTaskTimeout" separator=".">
+  <suffix name="PNG"/>
+  <suffix name="JPEG"/>
+  <suffix name="WEBP"/>
+  <suffix name="Unknown"/>
+  <affected-histogram name="Canvas.ToBlob.IdleTaskTimeout"/>
+</histogram_suffixes>
+
 <histogram_suffixes name="CertificateTypeAlgorithms" separator=".">
   <owner>rsleevi@chromium.org</owner>
   <suffix name="DH" label="DH"/>