Addressing minor review comments in ExtensionProcessManager...

chrome/browser/extensions/extension_process_manager.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.
 
 #include "chrome/browser/extensions/extension_process_manager.h"
 
 #include "chrome/browser/browsing_instance.h"
 #include "chrome/browser/extensions/extension_host.h"
 #include "chrome/browser/extensions/extensions_service.h"
 #include "chrome/browser/profile.h"
@@ skipping 67 matching lines @@
 ExtensionHost* ExtensionProcessManager::CreateBackgroundHost(
     Extension* extension, const GURL& url) {
   ExtensionHost* host =
       new ExtensionHost(extension, GetSiteInstanceForURL(url), url);
   host->CreateRenderView(NULL);  // create a RenderViewHost with no view
   OnExtensionHostCreated(host, true);
   return host;
 }
 
 void ExtensionProcessManager::RegisterExtensionProcess(
-    std::string extension_id, int process_id) {
+    const std::string& extension_id, int process_id) {
   ProcessIDMap::const_iterator it = process_ids_.find(extension_id);
   if (it != process_ids_.end() && (*it).second == process_id)
     return;
 
+  // Extension ids should get removed from the map before the process ids get
+  // reused from a dead renderer.
+  DCHECK(it == process_ids_.end());
   process_ids_[extension_id] = process_id;
 
   ExtensionsService* extension_service =
       browsing_instance_->profile()->GetExtensionsService();
 
   std::vector<std::string> page_action_ids;
   Extension* extension = extension_service->GetExtensionById(extension_id);
   for (PageActionMap::const_iterator i = extension->page_actions().begin();
        i != extension->page_actions().end(); ++i) {
     page_action_ids.push_back(i->first);
@@ skipping 73 matching lines @@
 void ExtensionProcessManager::OnExtensionHostCreated(ExtensionHost* host,
                                                      bool is_background) {
   all_hosts_.insert(host);
   if (is_background)
     background_hosts_.insert(host);
   NotificationService::current()->Notify(
       NotificationType::EXTENSION_HOST_CREATED,
       Source<ExtensionProcessManager>(this),
       Details<ExtensionHost>(host));
 }