Move Chrome.MessageLoopProblem histogram declaration from google3 and take ownership

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 72f17135081ddc7725fa7c5b2c093803ac6f2857..7efd2a0ae552e5a6cfb2488c35f467cfdc6d100d 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -4856,6 +4856,15 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Chrome.MessageLoopProblem" enum="MessageLoopProblems">
+  <owner>gab@chromium.org</owner>
+  <summary>
+    Track set of Windows errors inside the meessage loop/pump system, where
+    system calls fail, and we try to gracefully recover.  These errors should
+    really never happen, so we should be sure to look closer if they do.
+  </summary>
+</histogram>
+
 <histogram name="Chrome.SearchSelectExempt" enum="SearchEngine">
   <obsolete>
     Deprecated 8/2013. No longer tracked.
@@ -78607,6 +78616,12 @@ To add a new entry, add it with any value and run test to compute valid value.
   <int value="5" label="Moderate pressure to no pressure"/>
 </enum>
 
+<enum name="MessageLoopProblems" type="int">
+  <int value="0" label="Message Post"/>
+  <int value="1" label="Completion Post"/>
+  <int value="2" label="Set Timer"/>
+</enum>
+
 <enum name="MetadataReadResult" type="int">
   <int value="0" label="Success"/>
   <int value="1" label="Open failure"/>