Prioritize which HTTP requests get a socket first by adding a priority level ...

chrome/browser/renderer_host/resource_dispatcher_host.cc

Index: chrome/browser/renderer_host/resource_dispatcher_host.cc
===================================================================
--- chrome/browser/renderer_host/resource_dispatcher_host.cc	(revision 12453)
+++ chrome/browser/renderer_host/resource_dispatcher_host.cc	(working copy)
@@ -53,7 +53,7 @@
 #endif
 
 // Uncomment to enable logging of request traffic.
-//#define LOG_RESOURCE_DISPATCHER_REQUESTS
+// #define LOG_RESOURCE_DISPATCHER_REQUESTS
 
 #ifdef LOG_RESOURCE_DISPATCHER_REQUESTS
 # define RESOURCE_LOG(stuff) LOG(INFO) << stuff
@@ -328,6 +328,18 @@
   request->set_context(context);
   request->set_origin_pid(request_data.origin_pid);
 
+  // If the request is for the top level page or a frame/iframe, then we should
+  // prioritize it higher than other resource types.  Currently, we just use
+  // priorities 1 and 0.
+  // TODO(willchan): Revisit the actual priorities when looking at considering
+  // boosting priorities for requests for the foreground tab.
+  if (request_data.resource_type == ResourceType::MAIN_FRAME ||
+      request_data.resource_type == ResourceType::SUB_FRAME) {
+    request->set_priority(1);
+  } else {
+    request->set_priority(0);
+  }
+
   // Set upload data.
   uint64 upload_size = 0;
   if (!request_data.upload_content.empty()) {
@@ -377,7 +389,8 @@
                            request_data.main_frame_origin,
                            request_data.resource_type,
                            upload_size);
-  extra_info->allow_download = ResourceType::IsFrame(request_data.resource_type);
+  extra_info->allow_download =
+      ResourceType::IsFrame(request_data.resource_type);
   request->set_user_data(extra_info);  // takes pointer ownership
 
   BeginRequestInternal(request);
@@ -511,7 +524,7 @@
                            "null",  // frame_origin
                            "null",  // main_frame_origin
                            ResourceType::SUB_RESOURCE,
-                           0 /* upload_size */ );
+                           0 /* upload_size */);
   extra_info->allow_download = true;
   extra_info->is_download = true;
   request->set_user_data(extra_info);  // Takes pointer ownership.