Add a command line flag (--enable-fixed-position-compositing) for enabling compositing

content/browser/renderer_host/browser_render_process_host.cc

 // Copyright (c) 2011 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.
 
 // Represents the browser side of the browser <--> renderer communication
 // channel. There will be one RenderProcessHost per renderer process.
 
 #include "content/browser/renderer_host/browser_render_process_host.h"
 
 #include <algorithm>
@@ skipping 549 matching lines @@
     switches::kDisableJavaScriptI18NAPI,
     switches::kDisableLocalStorage,
     switches::kDisableLogging,
     switches::kDisableSeccompSandbox,
     switches::kDisableSessionStorage,
     switches::kDisableSharedWorkers,
     switches::kDisableSpeechInput,
     switches::kDisableWebAudio,
     switches::kDisableWebSockets,
     switches::kEnableAccessibilityLogging,
+    switches::kEnableCompositingForFixedPosition,

[jamesr, 2011/10/27 06:19:52]

why is this here? i know we tend to cargo-cult it all the time but I can't
figure out what on earth it is for.

the way this flag works is it's checked in the browser process when building the
WebPreferences object for a given tab and then sent down via IPC. so why would
you want the switch to be on the renderer's command line?

     switches::kEnableDCHECK,
     switches::kEnableGPUServiceLogging,
     switches::kEnableGPUClientLogging,
     switches::kEnableLogging,
     switches::kEnableMediaStream,
     switches::kEnableStrictSiteIsolation,
     switches::kDisableFullScreen,
     switches::kEnablePepperTesting,
 #if defined(OS_MACOSX)
     // Allow this to be set when invoking the browser and relayed along.
@@ skipping 412 matching lines @@
 void BrowserRenderProcessHost::OnRevealFolderInOS(const FilePath& path) {
   // Only honor the request if appropriate persmissions are granted.
   if (ChildProcessSecurityPolicy::GetInstance()->CanReadFile(id(), path))
     content::GetContentClient()->browser()->OpenItem(path);
 }
 
 void BrowserRenderProcessHost::OnSavedPageAsMHTML(int job_id, int64 data_size) {
   content::GetContentClient()->browser()->GetMHTMLGenerationManager()->
       MHTMLGenerated(job_id, data_size);
 }