[Mojo-Loading] Implement URLLoader::SetPriority

content/common/url_loader.mojom

Index: content/common/url_loader.mojom
diff --git a/content/common/url_loader.mojom b/content/common/url_loader.mojom
index 5429331b06064cda930e9b515472a357b57b85fa..102065a354a4ebb7abae0bf65abcca580f66e16c 100644
--- a/content/common/url_loader.mojom
+++ b/content/common/url_loader.mojom
@@ -16,12 +16,27 @@ struct URLRequestRedirectInfo;
 [Native]
 struct URLLoaderStatus;
 
+// This enum corresponds to net::RequestPriority. See its comments for details.
+enum RequestPriority {
+  kThrottled = 0,
+  kIdle,
+  kLowest,
+  kLow,
+  kMedium,
+  kHighest
+};
+
 // Destroying a URLLoader will cancel the associated request.
 interface URLLoader {
   // If the associated request has |auto_follow_redirects| set to false,
   // then upon receiving an URLResponse with a non-NULL |redirect_url| field,
   // |FollowRedirect| may be called to load the URL indicated by the redirect.
   FollowRedirect();
+
+  // Sets the request priority.
+  // |intra_priority_value| is a lesser priority which is used to prioritize
+  // requests within a given priority level.
+  SetPriority(RequestPriority priority, int32 intra_priority_value);
 };
 
 // Opaque handle passed from the browser process to a child process to manage