Content Settings: Add RevocationObserver to measure when permissions are revoked

chrome/browser/permissions/permission_util.h

Index: chrome/browser/permissions/permission_util.h
diff --git a/chrome/browser/permissions/permission_util.h b/chrome/browser/permissions/permission_util.h
index eb0e066f2484c2825e7ed059fe9ebcb7ac7df00f..b4f86ea93658921f9995d29478f33b9957ae8611 100644
--- a/chrome/browser/permissions/permission_util.h
+++ b/chrome/browser/permissions/permission_util.h
@@ -8,8 +8,12 @@
 #include <string>
 
 #include "base/macros.h"
+#include "components/content_settings/core/common/content_settings.h"
 #include "components/content_settings/core/common/content_settings_types.h"
 
+class GURL;
+class Profile;
+
 namespace content {
 enum class PermissionType;
 }  // namespace content
@@ -29,6 +33,23 @@ class PermissionUtil {
   static bool GetPermissionType(ContentSettingsType type,
                                 content::PermissionType* out);
 
+  // Helper method which proxies
+  // HostContentSettingsMap::SetContentSettingDefaultScope(). Checks the content
+  // setting value before and after the change to determine whether it has gone
+  // from ALLOW to BLOCK or ASK, and records metrics accordingly. Should be
+  // called from UI code when a user changes permissions for a particular origin
+  // pair. Returns true if the permission was revoked.
+  // TODO(tsergeant): This is a temporary solution to begin gathering metrics.
+  // We should integrate this better with the permissions layer. See
+  // crbug.com/469221.

[felt, 2016/04/04 13:20:27]

Seems a little weird to have this return a boolean for revocation. I'm wondering
why any caller would care about it. Is that to make testing easier?

[tsergeant, 2016/04/04 23:48:28]

Yeah, it was only used for testing. I've removed it, since I'm using
HistogramTester now anyway.

+  static bool SetContentSettingAndRecordRevocation(
+      Profile* profile,
+      const GURL& primary_url,
+      const GURL& secondary_url,
+      ContentSettingsType content_type,
+      std::string resource_identifier,
+      ContentSetting setting);
+
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(PermissionUtil);
 };