Handle extension webrequest API on the IO thread. This speeds up blocking event

chrome/renderer/extensions/extension_process_bindings.cc

Index: chrome/renderer/extensions/extension_process_bindings.cc
diff --git a/chrome/renderer/extensions/extension_process_bindings.cc b/chrome/renderer/extensions/extension_process_bindings.cc
index 7903875777308c7a86ab9b2234fa4b63600343c9..02f799f6569305e068eac2118fffb7a3af0048b8 100644
--- a/chrome/renderer/extensions/extension_process_bindings.cc
+++ b/chrome/renderer/extensions/extension_process_bindings.cc
@@ -168,6 +168,9 @@ class ExtensionImpl : public ExtensionBase {
     } else if (name->Equals(v8::String::New("StartRequest"))) {
       return v8::FunctionTemplate::New(StartRequest,
                                        v8::External::New(this));
+    } else if (name->Equals(v8::String::New("StartRequestForIOThread"))) {
+      return v8::FunctionTemplate::New(StartRequestForIOThread,
+                                       v8::External::New(this));
     } else if (name->Equals(v8::String::New("GetRenderViewId"))) {
       return v8::FunctionTemplate::New(GetRenderViewId);
     } else if (name->Equals(v8::String::New("SetIconCommon"))) {
@@ -389,7 +392,7 @@ class ExtensionImpl : public ExtensionBase {
   // contains the request's arguments.
   // Steals value_args contents for efficiency.
   static v8::Handle<v8::Value> StartRequestCommon(
-      const v8::Arguments& args, ListValue* value_args) {
+      const v8::Arguments& args, ListValue* value_args, bool for_io_thread) {
     ExtensionImpl* v8_extension = GetFromArguments<ExtensionImpl>(args);
 
     // Get the current RenderView so that we can send a routed IPC message from
@@ -430,8 +433,13 @@ class ExtensionImpl : public ExtensionBase {
     params.request_id = request_id;
     params.has_callback = has_callback;
     params.user_gesture = webframe->isProcessingUserGesture();
-    renderview->Send(new ExtensionHostMsg_Request(
-        renderview->routing_id(), params));
+    if (for_io_thread) {
+      renderview->Send(new ExtensionHostMsg_RequestForIOThread(
+          renderview->routing_id(), params));
+    } else {
+      renderview->Send(new ExtensionHostMsg_Request(
+          renderview->routing_id(), params));
+    }
 
     return v8::Undefined();
   }
@@ -451,7 +459,28 @@ class ExtensionImpl : public ExtensionBase {
       return v8::Undefined();
     }
 
-    return StartRequestCommon(args, static_cast<ListValue*>(value_args.get()));
+    return StartRequestCommon(args, static_cast<ListValue*>(value_args.get()),
+                              false);
+  }
+
+  // Starts an API request to the browser, with an optional callback.  The
+  // callback will be dispatched to EventBindings::HandleResponse.
+  static v8::Handle<v8::Value> StartRequestForIOThread(

[Mihai Parparita -not on Chrome, 2011/06/08 01:11:59]

This seems very similar to StartRequest. Can the for_io_thread bool just be a JS
parameter to StartRequest?

[Matt Perry, 2011/06/08 20:47:00]

Done.

+      const v8::Arguments& args) {
+    std::string str_args = *v8::String::Utf8Value(args[1]);
+    base::JSONReader reader;
+    scoped_ptr<Value> value_args;
+    value_args.reset(reader.JsonToValue(str_args, false, false));
+
+    // Since we do the serialization in the v8 extension, we should always get
+    // valid JSON.
+    if (!value_args.get() || !value_args->IsType(Value::TYPE_LIST)) {
+      NOTREACHED() << "Invalid JSON passed to StartRequest.";

[Mihai Parparita -not on Chrome, 2011/06/08 01:11:59]

If you do keep this function, the message here should be updated to say
StartRequestForIOThread.

+      return v8::Undefined();
+    }
+
+    return StartRequestCommon(args, static_cast<ListValue*>(value_args.get()),
+                              true);
   }
 
   static bool ConvertImageDataToBitmapValue(
@@ -520,7 +549,7 @@ class ExtensionImpl : public ExtensionBase {
     ListValue list_value;
     list_value.Append(dict);
 
-    return StartRequestCommon(args, &list_value);
+    return StartRequestCommon(args, &list_value, false);
   }
 
   static v8::Handle<v8::Value> GetRenderViewId(const v8::Arguments& args) {