Add UMA metric for tracking listeners for blocking touch before page finished loading

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 ff42b03ba9525d87125c4b3bbe095742b3a6ab49..a17805628c7897084b4a4856fd9b75a5906ef710 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -12111,6 +12111,15 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Event.Touch.TouchBlockingOnPageload"
+    enum="BooleanCanceledTouchOnPageload">
+  <owner>tdresser@chromium.org</owner>
+  <summary>
+    Count the canceled touch start and first touch move listeners before page
+    finishes loading.
+  </summary>
+</histogram>
+
 <histogram name="Event.TouchDuration" units="ms">
   <owner>kuscher@google.com</owner>
   <owner>rbyers@chromium.org</owner>
@@ -62217,6 +62226,11 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <int value="1" label="Hit"/>
 </enum>
 
+<enum name="BooleanCanceledTouchOnPageload" type="int">
+  <int value="0" label="Uncanceled Touchs"/>
+  <int value="1" label="Canceled Touchs"/>
+</enum>
+
 <enum name="BooleanCanCheckUrl" type="int">
   <int value="0" label="Skipped"/>
   <int value="1" label="Can check"/>