Revert of Remove about:srcdoc url conversion.

content/browser/renderer_host/render_process_host_impl.cc

 // Copyright 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.
 
 // Represents the browser side of the browser <--> renderer communication
 // channel. There will be one RenderProcessHost per renderer process.
 
 #include "content/browser/renderer_host/render_process_host_impl.h"
 
 #include <algorithm>
@@ skipping 2351 matching lines @@
 
   if (!url->is_valid()) {
     // Have to use about:blank for the denied case, instead of an empty GURL.
     // This is because the browser treats navigation to an empty GURL as a
     // navigation to the home page. This is often a privileged page
     // (chrome://newtab/) which is exactly what we don't want.
     *url = GURL(url::kAboutBlankURL);
     return;
   }
 
+  if (url->SchemeIs(url::kAboutScheme)) {
+    // The renderer treats all URLs in the about: scheme as being about:blank.
+    // Canonicalize about: URLs to about:blank.
+    *url = GURL(url::kAboutBlankURL);
+  }
+
   if (!policy->CanRequestURL(rph->GetID(), *url)) {
     // If this renderer is not permitted to request this URL, we invalidate the
     // URL.  This prevents us from storing the blocked URL and becoming confused
     // later.
     VLOG(1) << "Blocked URL " << url->spec();
     *url = GURL(url::kAboutBlankURL);
   }
 }
 
 // static
@@ skipping 612 matching lines @@
   LOG(ERROR) << "Terminating render process for bad Mojo message: " << error;
 
   // The ReceivedBadMessage call below will trigger a DumpWithoutCrashing. Alias
   // enough information here so that we can determine what the bad message was.
   base::debug::Alias(&error);
   bad_message::ReceivedBadMessage(render_process_id,
                                   bad_message::RPH_MOJO_PROCESS_ERROR);
 }
 
 }  // namespace content