Ok, here is a different approach at this change.

chrome/browser/renderer_host/browser_render_process_host.cc

 // Copyright (c) 2009 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 "chrome/browser/renderer_host/browser_render_process_host.h"
 
 #include <algorithm>
@@ skipping 575 matching lines @@
 void BrowserRenderProcessHost::InitExtensions() {
   // TODO(aa): Should only bother sending these function names if this is an
   // extension process.
   std::vector<std::string> function_names;
   ExtensionFunctionDispatcher::GetAllFunctionNames(&function_names);
   Send(new ViewMsg_Extension_SetFunctionNames(function_names));
 }
 
 void BrowserRenderProcessHost::SendUserScriptsUpdate(
     base::SharedMemory *shared_memory) {
+  // Don't send user scripts to extension processes. We currently don't allow
+  // user scripts to run in extensions, so it would be pointless. It would also
+  // mess up the crash reporting, which sends a different set of "active"
+  // extensions depending on whether the process is an extension or renderer
+  // process.
+  if (extension_process_)
+    return;
+
   // Process is being started asynchronously.  We'll end up calling
   // InitUserScripts when it's created which will call this again.
   if (child_process_.get() && child_process_->IsStarting())
     return;
 
   base::SharedMemoryHandle handle_for_process;
   if (!shared_memory->ShareToProcess(GetHandle(), &handle_for_process)) {
     // This can legitimately fail if the renderer asserts at startup.
     return;
   }
@@ skipping 382 matching lines @@
         IPC::PlatformFileForTransit(),
         std::vector<std::string>(),
         std::string(),
         false));
   }
 }
 
 void BrowserRenderProcessHost::EnableAutoSpellCorrect(bool enable) {
   Send(new ViewMsg_SpellChecker_EnableAutoSpellCorrect(enable));
 }