Pass WebKit priority changes and parsing messages up to the browser process.

content/browser/loader/resource_dispatcher_host_impl.cc

Index: content/browser/loader/resource_dispatcher_host_impl.cc
diff --git a/content/browser/loader/resource_dispatcher_host_impl.cc b/content/browser/loader/resource_dispatcher_host_impl.cc
index 9dcf49e5fe3cbec993ffd3faf6eee11dd7649677..0d94b5e6d081bacaf514e9c7a7b00890f7d39f22 100644
--- a/content/browser/loader/resource_dispatcher_host_impl.cc
+++ b/content/browser/loader/resource_dispatcher_host_impl.cc
@@ -203,9 +203,9 @@ void RemoveDownloadFileFromChildSecurityPolicy(int child_id,
 #pragma warning(default: 4748)
 #endif
 
-net::RequestPriority DetermineRequestPriority(
-    const ResourceHostMsg_Request& request_data) {
-  switch (request_data.priority) {
+net::RequestPriority ConvertWebKitPriorityToNetPriority(
+    const WebKit::WebURLRequest::Priority& priority) {
+  switch (priority) {
     case WebKit::WebURLRequest::PriorityVeryHigh:
       return net::HIGHEST;
 
@@ -792,6 +792,7 @@ bool ResourceDispatcherHostImpl::OnMessageReceived(
     IPC_MESSAGE_HANDLER(ResourceHostMsg_UploadProgress_ACK, OnUploadProgressACK)
     IPC_MESSAGE_HANDLER(ResourceHostMsg_CancelRequest, OnCancelRequest)
     IPC_MESSAGE_HANDLER(ResourceHostMsg_FollowRedirect, OnFollowRedirect)
+    IPC_MESSAGE_HANDLER(ResourceHostMsg_DidChangePriority, OnDidChangePriority)
     IPC_MESSAGE_HANDLER(ViewHostMsg_SwapOut_ACK, OnSwapOutACK)
     IPC_MESSAGE_HANDLER(ViewHostMsg_DidLoadResourceFromMemoryCache,
                         OnDidLoadResourceFromMemoryCache)
@@ -922,7 +923,8 @@ void ResourceDispatcherHostImpl::BeginRequest(
 
   request->set_load_flags(load_flags);
 
-  request->set_priority(DetermineRequestPriority(request_data));
+  request->set_priority(ConvertWebKitPriorityToNetPriority(
+      request_data.priority));
 
   // Resolve elements from request_body and prepare upload data.
   if (request_data.request_body) {
@@ -1127,6 +1129,20 @@ void ResourceDispatcherHostImpl::OnFollowRedirect(
   }
 }
 
+void ResourceDispatcherHostImpl::OnDidChangePriority(
+    int request_id,
+    WebKit::WebURLRequest::Priority priority) {
+  int child_id = filter_->child_id();
+  LoaderMap::iterator it = pending_loaders_.find(
+      GlobalRequestID(child_id, request_id));
+  if (it == pending_loaders_.end()) {
+    // PendingRequest likely removed while this IPC was in flight.
+    return;
+  }
+  const linked_ptr<ResourceLoader>& loader = it->second;
+  loader->ChangePriority(ConvertWebKitPriorityToNetPriority(priority));

[darin (slow to review), 2013/02/06 05:04:13]

Maybe instead of routing this notification through the ResourceHandler and
ResourceThrottle interfaces, you could just pass the notification directly to
the ResourceScheduler.  It could maintain a mapping from (child_id, request_id)
to scheduled requests.

+}
+
 ResourceRequestInfoImpl* ResourceDispatcherHostImpl::CreateRequestInfo(
     int child_id,
     int route_id,