[Extensions] Record the extension function names which send a bad message.

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 1f090b01498b2db69562cbfbddb134e109d5f5c5..ee04c3c7240426ad5bf7f9049dfdf34d8fa5d66b 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -8368,6 +8368,16 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="Extensions.BadMessageFunctionName" enum="ExtensionFunctions">
+  <owner>kalman@chromium.org</owner>
+  <summary>
+    The number of times each Extension function call sends a bad message,
+    killing the renderer. This may indicate a bug in that API's implementation
+    on the renderer. Note a similar, aggregate metric is BadMessageTerminate_EFD
+    which counts the number of bad messages that are sent overall.
+  </summary>
+</histogram>
+
 <histogram name="Extensions.CheckForExternalUpdatesTime">
   <owner>rkaplow@chromium.org</owner>
   <summary>
@@ -41153,8 +41163,8 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   <owner>ulan@chromium.org</owner>
   <summary>
     Number of garbage collections that a detached global context survives,
-    recorded after each major garbage collection.
-    Values greater than 7 indicate a memory leak.
+    recorded after each major garbage collection. Values greater than 7 indicate
+    a memory leak.
   </summary>
 </histogram>