Final batch adding real histogram values for extension events.

chrome/browser/extensions/api/preference/preference_helpers.h

Index: chrome/browser/extensions/api/preference/preference_helpers.h
diff --git a/chrome/browser/extensions/api/preference/preference_helpers.h b/chrome/browser/extensions/api/preference/preference_helpers.h
index ba227af44a617d8f2c91a669ca97369148ae31bb..02d77ec07186a56574e52211a1732d5d841fc59e 100644
--- a/chrome/browser/extensions/api/preference/preference_helpers.h
+++ b/chrome/browser/extensions/api/preference/preference_helpers.h
@@ -7,6 +7,7 @@
 
 #include <string>
 
+#include "extensions/browser/extension_event_histogram_value.h"
 #include "extensions/browser/extension_prefs_scope.h"
 #include "extensions/common/permissions/permission_set.h"
 
@@ -35,13 +36,13 @@ const char* GetLevelOfControl(
 // key-value for the level of control the extension has over |browser_pref| is
 // injected into the first item of |args|, which must be of type
 // DictionaryValue.
-void DispatchEventToExtensions(
-    Profile* profile,
-    const std::string& event_name,
-    base::ListValue* args,
-    extensions::APIPermission::ID permission,
-    bool incognito,
-    const std::string& browser_pref);
+void DispatchEventToExtensions(Profile* profile,
+                               events::HistogramValue histogram_value,
+                               const std::string& event_name,
+                               base::ListValue* args,

[Alexei Svitkine (slow), 2015/07/21 19:09:40]

Nit: Seems like this param can be const. Maybe even const ref?

[not at google - send to devlin, 2015/07/21 20:37:39]

Looking at the implementation of this method, it should actually be a
scoped_ptr<ListValue> - it takes a copy, which is really silly.

Because you've brought it up - and DeepCopies make me sad - I'll fix it up in a
follow-up. I want this patch to be as straightforward as possible, no chance of
introducing a bug, which a scoped_ptr<ListValue> change may cause.

+                               extensions::APIPermission::ID permission,
+                               bool incognito,
+                               const std::string& browser_pref);
 
 }  // namespace preference_helpers
 }  // namespace extensions