Collecting statistics on iframe permissions use.

content/child/permissions/permission_dispatcher.cc

Index: content/child/permissions/permission_dispatcher.cc
diff --git a/content/child/permissions/permission_dispatcher.cc b/content/child/permissions/permission_dispatcher.cc
index eb5ac4538f0f9caf86adea7769ed9ab016e18e7b..1784133788b31be6499b807c769e208c8b0b1abb 100644
--- a/content/child/permissions/permission_dispatcher.cc
+++ b/content/child/permissions/permission_dispatcher.cc
@@ -48,6 +48,8 @@ PermissionStatus GetPermissionStatus(blink::WebPermissionStatus status) {
   return PERMISSION_STATUS_DENIED;
 }
 
+// PERMISSION_STATUS_NUM is only a boundary value and should never be passed
+// into this function for |status|.
 blink::WebPermissionStatus GetWebPermissionStatus(PermissionStatus status) {
   switch (status) {
     case PERMISSION_STATUS_GRANTED:
@@ -56,9 +58,11 @@ blink::WebPermissionStatus GetWebPermissionStatus(PermissionStatus status) {
       return blink::WebPermissionStatusDenied;
     case PERMISSION_STATUS_ASK:
       return blink::WebPermissionStatusPrompt;
+    case PERMISSION_STATUS_NUM:
+      NOTREACHED();
+      break;
   }
 
-  NOTREACHED();
   return blink::WebPermissionStatusDenied;
 }