Implement permission embargo suppression metrics.

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 b8faf9417ee6085d3141b6bfccbc060073bc519e..60193a0decd098c580ff5cd556555aac758f3367 100644
--- a/chrome/browser/permissions/permission_util.h
+++ b/chrome/browser/permissions/permission_util.h
@@ -35,6 +35,40 @@ enum PermissionAction {
   PERMISSION_ACTION_NUM,
 };
 
+// Identifies the source or reason for a permission status being returned. This
+// enum backs an UMA histogram and must be treated as append-only.
+enum class PermissionStatusSource {
+  // The reason for the status is not specified.
+  UNSPECIFIED,
+
+  // The status is the result of being blocked due to the user dismissing a
+  // permission prompt multiple times.
+  MULTIPLE_DISMISSALS,
+
+  // The status is the result of being blocked because the permission is on the
+  // safe browsing blacklist.
+  SAFE_BROWSING_BLACKLIST,
+
+  // The status is the result of being blocked by the permissions kill switch.
+  KILL_SWITCH,
+
+  // Must be kept last.
+  NUM

[raymes, 2017/02/22 23:13:50]

nit: I don't think this is needed anymore.

[dominickn, 2017/02/22 23:38:55]

Done.

+};
+
+struct PermissionResult {
+  PermissionResult(ContentSetting content_setting,
+                   PermissionStatusSource source);
+  ~PermissionResult();
+
+  ContentSetting content_setting;
+  PermissionStatusSource source;
+};

[raymes, 2017/02/22 23:13:50]

I think it would be good to move these into their own permission_result.h file
at some point (PermissionResult and PermissionStatusSource). Doesn't have to be
in this CL though.

[dominickn, 2017/02/22 23:38:54]

Acknowledged.

+
+struct PermissionTypeHash {
+  std::size_t operator()(const content::PermissionType& type) const;
+};

[raymes, 2017/02/22 23:13:50]

Is this needed?

[dominickn, 2017/02/22 23:38:55]

Odd, looks like whatever used it has been removed. Must have been timloh's
refactoring.

+
 // A utility class for permissions.
 class PermissionUtil {
  public: