Modify Blink.Canvas.toDataURL UMA performance metrics

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 dbf554246285e39c0fa2b17c7777b698507c2ce5..59b14a800c8f4fee1841921e0562a3cffe1a8bce 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -102553,13 +102553,33 @@ value.
 </histogram_suffixes>
 
 <histogram_suffixes name="BlinkCanvasToDataURLTime" separator=".">
-  <suffix name="BMP"/>
-  <suffix name="GIF"/>
-  <suffix name="ICON"/>
+  <suffix name="BMP">
+    <obsolete>
+      Removed in Oct 2016
+    </obsolete>
+  </suffix>
+  <suffix name="GIF">
+    <obsolete>
+      Removed in Oct 2016
+    </obsolete>
+  </suffix>
+  <suffix name="ICON">
+    <obsolete>
+      Removed in Oct 2016
+    </obsolete>
+  </suffix>
   <suffix name="JPEG"/>
   <suffix name="PNG"/>
-  <suffix name="TIFF"/>
-  <suffix name="Unknown"/>
+  <suffix name="TIFF">
+    <obsolete>
+      Removed in Oct 2016
+    </obsolete>
+  </suffix>
+  <suffix name="Unknown">
+    <obsolete>
+      Removed in Oct 2016
+    </obsolete>
+  </suffix>
   <suffix name="WEBP"/>
   <affected-histogram name="Blink.Canvas.ToDataURL"/>
 </histogram_suffixes>