Remove support for special "sign in process" state.

chrome/renderer/chrome_content_renderer_client.cc

 // 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.
 
 #include "chrome/renderer/chrome_content_renderer_client.h"
 
 #include "base/command_line.h"
 #include "base/debug/crash_logging.h"
 #include "base/logging.h"
 #include "base/metrics/field_trial.h"
@@ skipping 1255 matching lines @@
     return true;
   }
 
   // For now, we skip the rest for POST submissions.  This is because
   // http://crbug.com/101395 is more likely to cause compatibility issues
   // with hosted apps and extensions than WebUI pages.  We will remove this
   // check when cross-process POST submissions are supported.
   if (http_method != "GET")
     return false;
 
-  // If this is the Signin process, fork all navigations originating from the
-  // renderer.  The destination page will then be bucketed back to this Signin
-  // process if it is a Signin url, or to another process if not.
-  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kSigninProcess)) {
-    // We never want to allow non-signin pages to fork-on-POST to a
-    // signin-related action URL. We'll need to handle this carefully once
-    // http://crbug.com/101395 is fixed. The CHECK ensures we don't forget.
-    CHECK_NE(http_method, "POST");
-    return true;
-  }
-
   // If |url| matches one of the prerendered URLs, stop this navigation and try
   // to swap in the prerendered page on the browser process. If the prerendered
   // page no longer exists by the time the OpenURL IPC is handled, a normal
   // navigation is attempted.
   if (prerender_dispatcher_.get() &&
       prerender_dispatcher_->IsPrerenderURL(url)) {
     *send_referrer = true;
     return true;
   }
 
@@ skipping 354 matching lines @@
   if (mime_type == content::kBrowserPluginMimeType) {
     return new extensions::ExtensionsGuestViewContainer(render_frame);
   } else {
     return new extensions::MimeHandlerViewContainer(
         render_frame, mime_type, original_url);
   }
 #else
   return NULL;
 #endif
 }