[DevTools] Fix frontend host race and assert.

chrome/browser/devtools/devtools_ui_bindings.cc

 // Copyright 2014 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/devtools/devtools_ui_bindings.h"
 
 #include "base/json/json_reader.h"
 #include "base/json/json_writer.h"
 #include "base/metrics/histogram.h"
 #include "base/prefs/scoped_user_pref_update.h"
@@ skipping 268 matching lines @@
  public:
   explicit FrontendWebContentsObserver(DevToolsUIBindings* ui_bindings);
   ~FrontendWebContentsObserver() override;
 
  private:
   // contents::WebContentsObserver:
   void RenderProcessGone(base::TerminationStatus status) override;
   void DidStartNavigationToPendingEntry(
       const GURL& url,
       content::NavigationController::ReloadType reload_type) override;
+  void DocumentAvailableInMainFrame() override;
   void DocumentOnLoadCompletedInMainFrame() override;
   void DidNavigateMainFrame(
       const content::LoadCommittedDetails& details,
       const content::FrameNavigateParams& params) override;
 
   DevToolsUIBindings* devtools_bindings_;
   DISALLOW_COPY_AND_ASSIGN(FrontendWebContentsObserver);
 };
 
 DevToolsUIBindings::FrontendWebContentsObserver::FrontendWebContentsObserver(
@@ skipping 32 matching lines @@
         const GURL& url,
         content::NavigationController::ReloadType reload_type) {
   devtools_bindings_->frontend_host_.reset(
       content::DevToolsFrontendHost::Create(
           web_contents()->GetMainFrame(),
           base::Bind(&DevToolsUIBindings::HandleMessageFromDevToolsFrontend,
                      base::Unretained(devtools_bindings_))));
 }
 
 void DevToolsUIBindings::FrontendWebContentsObserver::
+    DocumentAvailableInMainFrame() {
+  devtools_bindings_->DocumentAvailableInMainFrame();
+}
+
+void DevToolsUIBindings::FrontendWebContentsObserver::
     DocumentOnLoadCompletedInMainFrame() {
   devtools_bindings_->DocumentOnLoadCompletedInMainFrame();
 }
 
 void DevToolsUIBindings::FrontendWebContentsObserver::
     DidNavigateMainFrame(const content::LoadCommittedDetails& details,
                          const content::FrameNavigateParams& params) {
   devtools_bindings_->DidNavigateMainFrame();
 }
 
@@ skipping 126 matching lines @@
  return NULL;
 }
 
 DevToolsUIBindings::DevToolsUIBindings(content::WebContents* web_contents)
     : profile_(Profile::FromBrowserContext(web_contents->GetBrowserContext())),
       android_bridge_(DevToolsAndroidBridge::Factory::GetForProfile(profile_)),
       web_contents_(web_contents),
       delegate_(new DefaultBindingsDelegate(web_contents_)),
       devices_updates_enabled_(false),
       frontend_loaded_(false),
+      reattaching_(false),
       weak_factory_(this) {
   g_instances.Get().push_back(this);
   frontend_contents_observer_.reset(new FrontendWebContentsObserver(this));
   web_contents_->GetMutableRendererPrefs()->can_accept_load_drops = false;
 
   file_helper_.reset(new DevToolsFileHelper(web_contents_, profile_, this));
   file_system_indexer_ = new DevToolsFileSystemIndexer();
   extensions::ChromeExtensionWebContentsObserver::CreateForWebContents(
       web_contents_);
 
@@ skipping 623 matching lines @@
 void DevToolsUIBindings::AttachTo(
     const scoped_refptr<content::DevToolsAgentHost>& agent_host) {
   if (agent_host_.get())
     Detach();
   agent_host_ = agent_host;
   agent_host_->AttachClient(this);
 }
 
 void DevToolsUIBindings::Reattach() {
   DCHECK(agent_host_.get());
-  agent_host_->DetachClient();
-  agent_host_->AttachClient(this);
+  reattaching_ = true;
 }
 
 void DevToolsUIBindings::Detach() {
   if (agent_host_.get())
     agent_host_->DetachClient();
   agent_host_ = NULL;
 }
 
 bool DevToolsUIBindings::IsAttachedTo(content::DevToolsAgentHost* agent_host) {
   return agent_host_.get() == agent_host;
@@ skipping 25 matching lines @@
         base::JSONWriter::Write(*arg3, &json);
         javascript.append(", ").append(json);
       }
     }
   }
   javascript.append(");");
   web_contents_->GetMainFrame()->ExecuteJavaScript(
       base::UTF8ToUTF16(javascript));
 }
 
+void DevToolsUIBindings::DocumentAvailableInMainFrame() {
+  if (!reattaching_)
+    return;
+  reattaching_ = false;
+  agent_host_->DetachClient();
+  agent_host_->AttachClient(this);
+}
+
 void DevToolsUIBindings::DocumentOnLoadCompletedInMainFrame() {
   // In the DEBUG_DEVTOOLS mode, the DocumentOnLoadCompletedInMainFrame event
   // arrives before the LoadCompleted event, thus it should not trigger the
   // frontend load handling.
 #if !defined(DEBUG_DEVTOOLS)
   FrontendLoaded();
 #endif
 }
 
 void DevToolsUIBindings::DidNavigateMainFrame() {
   frontend_loaded_ = false;
 }
 
 void DevToolsUIBindings::FrontendLoaded() {
   if (frontend_loaded_)
     return;
   frontend_loaded_ = true;
 
   // Call delegate first - it seeds importants bit of information.
   delegate_->OnLoadCompleted();
 
   AddDevToolsExtensionsToClient();
   if (g_web_socket_api_channel)
     g_web_socket_api_channel->AttachedToBindings(this);
 }