Improve New Tab Page load performance

chrome/browser/dom_ui/chrome_url_data_manager.cc

 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/dom_ui/chrome_url_data_manager.h"
 
 #include "app/l10n_util.h"
 #include "base/file_util.h"
 #include "base/message_loop.h"
 #include "base/path_service.h"
 #include "base/string_util.h"
 #include "base/thread.h"
 #include "base/values.h"
 #include "chrome/browser/browser_process.h"
+#include "chrome/browser/chrome_thread.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/ref_counted_util.h"
 #include "chrome/common/url_constants.h"
 #include "googleurl/src/url_util.h"
 #include "net/base/io_buffer.h"
 #include "net/base/net_errors.h"
 #include "net/url_request/url_request.h"
 #include "net/url_request/url_request_file_job.h"
 #include "net/url_request/url_request_job.h"
 
@@ skipping 193 matching lines @@
   // Save this request so we know where to send the data.
   RequestID request_id = next_request_id_++;
   pending_requests_.insert(std::make_pair(request_id, job));
 
   // TODO(eroman): would be nicer if the mimetype were set at the same time
   // as the data blob. For now do it here, since NotifyHeadersComplete() is
   // going to get called once we return.
   job->SetMimeType(source->GetMimeType(path));
 
   // Forward along the request to the data source.
-  source->message_loop()->PostTask(FROM_HERE,
-      NewRunnableMethod(source, &DataSource::StartDataRequest,
-                        path, request_id));
+  MessageLoop* target_message_loop = source->MessageLoopForRequestPath(path);
+  if (!target_message_loop) {
+    // The DataSource is agnostic to which thread StartDataRequest is called
+    // on for this path.  Call directly into it from this thread, the IO
+    // thread.
+    source->StartDataRequest(path, request_id);
+  } else {
+    // The DataSource wants StartDataRequest to be called on a specific thread,
+    // usually the UI thread, for this path.
+    target_message_loop->PostTask(FROM_HERE,
+        NewRunnableMethod(source, &DataSource::StartDataRequest,
+                          path, request_id));
+  }
   return true;
 }
 
 void ChromeURLDataManager::RemoveRequest(URLRequestChromeJob* job) {
   // Remove the request from our list of pending requests.
   // If/when the source sends the data that was requested, the data will just
   // be thrown away.
   for (PendingRequestMap::iterator i = pending_requests_.begin();
        i != pending_requests_.end(); ++i) {
     if (i->second == job) {
@@ skipping 13 matching lines @@
     // feet of any method invoked here (we could trigger a callback).
     scoped_refptr<URLRequestChromeJob> job = i->second;
     pending_requests_.erase(i);
     job->DataAvailable(bytes);
   }
 }
 
 void ChromeURLDataManager::DataSource::SendResponse(
     RequestID request_id,
     RefCountedBytes* bytes) {
-  g_browser_process->io_thread()->message_loop()->PostTask(FROM_HERE,
+  ChromeThread::GetMessageLoop(ChromeThread::IO)->PostTask(FROM_HERE,

[Mark Mentovai, 2009/09/02 19:49:36]

Here.

       NewRunnableMethod(&chrome_url_data_manager,
                         &ChromeURLDataManager::DataAvailable,
                         request_id, scoped_refptr<RefCountedBytes>(bytes)));
 }
 
+MessageLoop* ChromeURLDataManager::DataSource::MessageLoopForRequestPath(
+    const std::string& path) const {
+  return message_loop_;
+}
+
 // static
 void ChromeURLDataManager::DataSource::SetFontAndTextDirection(
     DictionaryValue* localized_strings) {
   localized_strings->SetString(L"fontfamily",
       l10n_util::GetString(IDS_WEB_FONT_FAMILY));
   localized_strings->SetString(L"fontsize",
       l10n_util::GetString(IDS_WEB_FONT_SIZE));
 
   localized_strings->SetString(L"textdirection",
       (l10n_util::GetTextDirection() == l10n_util::RIGHT_TO_LEFT) ?
@@ skipping 94 matching lines @@
                                       net::ERR_INVALID_URL));
   }
 }
 
 URLRequestChromeFileJob::URLRequestChromeFileJob(URLRequest* request,
                                                  const FilePath& path)
     : URLRequestFileJob(request, path) {
 }
 
 URLRequestChromeFileJob::~URLRequestChromeFileJob() { }