Add a metric for autofilled Android credentials.

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 f956cff2a0b6455d02a7125daacbc0244449c501..5b6f862e8700eb13401dbc4f962ed00d659de2dc 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -27498,6 +27498,16 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="PasswordManager.OfferedToFillAndroidCredentials"

[Ilya Sherman, 2015/06/18 21:00:13]

nit: I'd suggest something like "SuggestionsIncludeAndroidAppCredentials" for
clarity -- IMO that name makes it clearer what the baseline is.

[msramek, 2015/06/19 10:44:24]

Done. Added "Fill" as prefix to clarify what is meant by suggestions.

+    enum="PasswordManagerOfferedAndroidCredentials">
+  <owner>msramek@chromium.org</owner>
+  <owner>engedy@chromium.org</owner>
+  <summary>
+    When offering to fill the username and password, whether at least one of the
+    credentials in the dropdown comes from an Android app.
+  </summary>
+</histogram>
+
 <histogram name="PasswordManager.OsPasswordStatus"
     enum="PasswordManagerOsPasswordStatus">
   <owner>dubroy@chromium.org</owner>
@@ -62121,6 +62131,11 @@ To add a new entry, add it with any value and run test to compute valid value.
   <int value="1" label="A password change form"/>
 </enum>
 
+<enum name="PasswordManagerOfferedAndroidCredentials" type="int">
+  <int value="0" label="No credentials are from Android"/>
+  <int value="1" label="At least one credential is from Android"/>

[Ilya Sherman, 2015/06/18 21:00:13]

nit: These names are somewhat long, given that they'll be shown as the left
column of a table-like display in the dashboard.  It's fine if you prefer to
keep these, but I'd suggest something more like "None from Android" and "1+ from
Android".

[msramek, 2015/06/19 10:44:23]

Makes sense. Done.

+</enum>
+
 <enum name="PasswordManagerOsPasswordStatus" type="int">
   <int value="0" label="Unknown"/>
   <int value="1" label="Unsupported platform"/>