Support Component Actions in the toolbar.

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 84d9004f76a1054c29a588bca645acf83cd020b4..c65c9959e1f96b90298566267c0f93e1c7f6e6b9 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -45924,6 +45924,26 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <summary>Number of retries until the final response was recorded.</summary>
 </histogram>
 
+<histogram name="ToolbarActionsModel.ComponentActionsCount">

[Ilya Sherman, 2015/08/06 15:55:23]

It looks like you're introducing a new top-level group name,
ToolbarActionsModel.  This might be appropriate, but just to make sure: Have you
considered whether there is an existing top-level group name that's appropriate
for these histograms?  And, if not, is there a more general (but still
reasonably specific) name that you could choose for the top-level group?  For
example, you could do choose "Toolbar.ActionsModel.*".

[apacible, 2015/08/06 17:50:46]

Talked to rdevlin.cronin@ about a potential top-level group name; switched to
Toolbar.ActionsModel.*. Thanks for the suggestions!

+  <owner>rdevlin.cronin@chromium.org</owner>
+  <summary>
+    The number of component action icons the Browser Actions Container knows
+    about (visible or in the overflow bucket). Does not count icons that have
+    been permanently hidden by the user. Measured once per startup per
+    (non-incognito) profile.
+  </summary>
+</histogram>
+
+<histogram name="ToolbarActionsModel.OverallActionsCount">
+  <owner>rdevlin.cronin@chromium.org</owner>
+  <summary>
+    The total number of action icons the Browser Actions Container knows about
+    (visible or in the overflow bucket). Does not count icons that have been
+    permanently hidden by the user. Measured once per startup per
+    (non-incognito) profile.
+  </summary>
+</histogram>
+
 <histogram name="TopSites.NumberOfApplyBlacklist">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <summary>The number of times TopSitesImpl::ApplyBlacklist is called.</summary>