Move message handlers that don't belong in RenderProcessHostImpl to their own files.

content/public/browser/content_browser_client.h

 // Copyright (c) 2012 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.
 
 #ifndef CONTENT_PUBLIC_BROWSER_CONTENT_BROWSER_CLIENT_H_
 #define CONTENT_PUBLIC_BROWSER_CONTENT_BROWSER_CLIENT_H_
 #pragma once
 
 #include <string>
 #include <utility>
@@ skipping 238 matching lines @@
   // certain operations, like cookie access. Returns NULL to indicate the
   // regular request context should be used.
   // This is called on the IO thread.
   virtual net::URLRequestContext* OverrideRequestContextForURL(
       const GURL& url, content::ResourceContext* context) = 0;
 
   // Create and return a new quota permission context.
   virtual QuotaPermissionContext* CreateQuotaPermissionContext() = 0;
 
   // Open the given file in the desktop's default manner.
+  // This is called on the UI thread.

[jam, 2012/05/17 20:39:06]

no need for these two comments, see the comment at the top:

The methods are assumed to be called on the UI thread unless otherwise
specified. Use this "escape hatch" sparingly, to thread unless otherwise
specified.

[Avi (use Gerrit), 2012/05/17 21:04:36]

Ah, thanks.

   virtual void OpenItem(const FilePath& path) = 0;
 
   // Show the given file in a file manager. If possible, select the file.
+  // This is called on the UI thread.
   virtual void ShowItemInFolder(const FilePath& path) = 0;
 
   // Informs the embedder that a certificate error has occured.  If overridable
   // is true, the user can ignore the error and continue.  If it's false, then
   // the certificate error is severe and the user isn't allowed to proceed.  The
   // embedder can call the callback asynchronously. If |cancel_request| is set
   // to true, the request will be cancelled immediately and the callback won't
   // be run.
   virtual void AllowCertificateError(
       int render_process_id,
@@ skipping 156 matching lines @@
   // This is called on a worker thread.
   virtual
       crypto::CryptoModuleBlockingPasswordDelegate* GetCryptoPasswordDelegate(
           const GURL& url) = 0;
 #endif
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_CONTENT_BROWSER_CLIENT_H_