Add metrics for user manually added exceptions

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 4d039a0327c757f69024ad623ec8de8a2cecbebb..b66b3115010488a785e2ce0b7838d9dfad662d57 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -5965,6 +5965,14 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="ContentSettings.NumberOfSingleTypeExceptions">

[Ilya Sherman, 2016/04/20 00:15:42]

nit: I'd name this histogram "ContentSettings.Exceptions", so that you'd end up
with histogram names like "ContentSettings.Exceptions.Cookies".

[lshang, 2016/04/20 05:24:02]

Done.

+  <owner>lshang@chromium.org</owner>
+  <summary>
+    The number of user defined content setting exceptions at browser start.
+    Suffixed with the name of content setting types.
+  </summary>
+</histogram>
+
 <histogram name="ContentSettings.PermissionActions" enum="PermissionAction">
   <obsolete>
     Removed 11/2015 in favor of Permissions.Action.*
@@ -88120,17 +88128,35 @@ To add a new entry, add it with any value and run test to compute valid value.
   <affected-histogram name="PLT.LoadType"/>
 </histogram_suffixes>
 
-<histogram_suffixes name="ContentSettingsTypes">
-  <suffix name="MidiSysEx" label="Midi SysEx permsision actions"/>
-  <suffix name="PushMessaging" label="Push messaging permission actions"/>
-  <suffix name="Notifications" label="Notification permission actions"/>
-  <suffix name="Geolocation" label="Geolocation permission actions"/>
-  <suffix name="ProtectedMedia" label="Protected media permission actions"/>
-  <suffix name="DurableStorage" label="Durable Storage permission actions"/>
-  <affected-histogram name="ContentSettings.PermissionActions"/>
-  <affected-histogram name="ContentSettings.PermissionActionsInsecureOrigin"/>
-  <affected-histogram name="ContentSettings.PermissionActionsSecureOrigin"/>
-  <affected-histogram name="Permissions.Requested.CrossOrigin"/>
+<histogram_suffixes name="ContentSettingsType" separator=".">
+  <suffix name="cookies" label="Cookies exceptions"/>

[Ilya Sherman, 2016/04/20 00:15:42]

Optional nit: It would be nice if the histogram name suffixes were written in
CamelCase rather than in lower-dashed-case, but it's not super important.  (So,
I'd probably recommend making this change if it's easy to implement in the C++
code, or not if it's not.)

[lshang, 2016/04/20 05:24:02]

I didn't find places in C++ code that can directly get ContentSettingsType's
CamelCase name. So I think we might just leave them here:-) But I will pay
attention of the name format in the future~ Thanks for the tip!

+  <suffix name="images" label="Images exceptions"/>
+  <suffix name="javascript" label="JavaScript exceptions"/>
+  <suffix name="plugins" label="Plugins exceptions"/>
+  <suffix name="popups" label="Popups exceptions"/>
+  <suffix name="geolocation" label="Geolocation exceptions"/>
+  <suffix name="notifications" label="Notification exceptions"/>
+  <suffix name="fullscreen" label="Fullscreen exceptions"/>
+  <suffix name="mouselock" label="Mouse lock exceptions"/>
+  <suffix name="media-stream-mic" label="Microphone exceptions"/>
+  <suffix name="media-stream-camera" label="Camera exceptions"/>
+  <suffix name="ppapi-broker" label="Ppapi broker exceptions"/>
+  <suffix name="automatic-downloads" label="Automatic downloads exceptions"/>
+  <suffix name="midi-sysex" label="Midi exceptions"/>
+  <suffix name="push-messaging" label="Push messaging exceptions"/>
+  <suffix name="protected-media-identifier" label="Protected media exceptions"/>
+  <suffix name="durable-storage" label="Durable Storage Exceptions"/>
+  <suffix name="keygen" label="Keygen exceptions"/>
+  <suffix name="background-sync" label="Background sync exceptions"/>
+  <suffix name="protocol-handler" label="Protocol handler exceptions"/>
+  <suffix name="mixed-script" label="Mixed script exceptions"/>
+  <suffix name="bluetooth-guard" label="Bluetooth guard exceptions"/>
+  <suffix name="auto-select-certificate" label="Auto-select cert exceptions"/>
+  <suffix name="ssl-cert-decisions" label="SSL cert decisions exceptions"/>
+  <suffix name="app-banner" label="App banner exceptions"/>
+  <suffix name="site-engagement" label="Site engagement exceptions"/>
+  <suffix name="usb-chooser-data" label="USB chooser data exceptions"/>

[Ilya Sherman, 2016/04/20 00:15:42]

nit: Please alphabetize this list of suffixes.

[lshang, 2016/04/20 05:24:02]

Done.

+  <affected-histogram name="ContentSettings.NumberOfSingleTypeExceptions"/>
 </histogram_suffixes>
 
 <histogram_suffixes name="ContextMenuType" separator=".">
@@ -91452,9 +91478,13 @@ To add a new entry, add it with any value and run test to compute valid value.
   <suffix name="DurableStorage" label="Durable Storage permission actions"/>
   <suffix name="AudioCapture" label="Microphone permission actions"/>
   <suffix name="VideoCapture" label="Camera permission actions"/>
+  <affected-histogram name="ContentSettings.PermissionActions"/>
+  <affected-histogram name="ContentSettings.PermissionActionsInsecureOrigin"/>
+  <affected-histogram name="ContentSettings.PermissionActionsSecureOrigin"/>
   <affected-histogram name="Permissions.Action"/>
   <affected-histogram name="Permissions.Action.InsecureOrigin"/>
   <affected-histogram name="Permissions.Action.SecureOrigin"/>
+  <affected-histogram name="Permissions.Requested.CrossOrigin"/>
 </histogram_suffixes>

[Ilya Sherman, 2016/04/20 00:15:42]

Hmm, the changes to this suffix list seem unrelated to the rest of the CL.  Am I
missing the connection?  If I'm not, please split this off to a separate CL, for
clarity of code change history.

[lshang, 2016/04/20 05:24:02]

Done. The moved suffix list should use PermissionTypes instead of
ContentSettingsTypes, and I merged these two suffix entries because they seem to
do the same thing. But yeah this change is not strongly related to this CL, so I
can move them to a new CL.:-)

 
 <histogram_suffixes name="PhysicalWebDebugActions" separator=".">