Add metrics for YouTube Flash embed rewrite.

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 5b8d8d55d0932452d28a99350da435a2388f3f5e..2dee790d0afe7663d681991022665257f585a1ed 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -42639,6 +42639,14 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Plugin.Flash.YouTubeRewrite" enum="YouTubeRewriteStatus">
+  <owner>mlamouri@chromium.org</owner>
+  <owner>kdsilva@google.org</owner>
+  <summary>
+    Records the YouTube Flash embed rewrite status when attempted.
+  </summary>
+</histogram>
+
 <histogram name="Plugin.FlashNavigateUsage" enum="FlashNavigateUsageType">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <summary>Record usage of PPB_Flash.Navigate() Pepper API.</summary>
@@ -95780,6 +95788,13 @@ To add a new entry, add it with any value and run test to compute valid value.
   <int value="1" label="XMLHttpRequestSendArrayBufferView"/>
 </enum>
 
+<enum name="YouTubeRewriteStatus" type="int">
+  <int value="0" label="SUCCESS"/>
+  <int value="1" label="SUCCESS_PARAMS_REWRITE"/>
+  <int value="2" label="SUCCESS_ENABLEJSAPI"/>
+  <int value="3" label="FAILURE_ENABLEJSAPI"/>
+</enum>
+
 </enums>
 
 <!-- Histogram suffixes list -->