Content Settings: Add RevocationObserver to measure when permissions are revoked

components/content_settings/core/browser/content_settings_observer.h

Index: components/content_settings/core/browser/content_settings_observer.h
diff --git a/components/content_settings/core/browser/content_settings_observer.h b/components/content_settings/core/browser/content_settings_observer.h
index 41868578942081c5020c86846319318f367aa47d..db6b1f594d703082a4c588ab2aa37481d89abb4f 100644
--- a/components/content_settings/core/browser/content_settings_observer.h
+++ b/components/content_settings/core/browser/content_settings_observer.h
@@ -24,6 +24,18 @@ class Observer {
   virtual ~Observer() {}
 };
 
+class RevocationObserver {
+ public:
+  virtual void OnContentSettingRevoked(

[raymes, 2016/03/17 02:05:43]

What are the downsides to adding this to Observer above?

[tsergeant, 2016/03/17 06:25:40]

I was having some problems with it initially, but I've added it to Observer with
a blank implementation and it works fine.

+      const GURL& primary_url,
+      const GURL& secondary_url,
+      ContentSettingsType content_type,
+      std::string resource_identifier) = 0;
+
+ protected:
+  virtual ~RevocationObserver() {}
+};
+
 }  // namespace content_settings
 
 #endif  // COMPONENTS_CONTENT_SETTINGS_CORE_BROWSER_CONTENT_SETTINGS_OBSERVER_H_