DevTools: issue detach notification when frontend api connection is kicked out.

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 383 matching lines @@
     bindings_->open_api_channel_ = nullptr;
 }
 
 void DevToolsUIBindings::WebSocketAPIChannel::DispatchOnClientHost(
     const std::string& message) {
   if (attached_proxy_)
     attached_proxy_->DispatchOnClientHost(message);
 }
 
 void DevToolsUIBindings::WebSocketAPIChannel::ConnectionClosed() {
+  if (bindings_) {
+    bindings_->CallClientFunction("DevToolsAPI.frontendAPIDetached",
+                                  nullptr, nullptr, nullptr);
+  }
   if (attached_proxy_)
     attached_proxy_->ConnectionClosed();
 }
 
 void DevToolsUIBindings::WebSocketAPIChannel::Attach(
     content::DevToolsExternalAgentProxy* proxy) {
   attached_proxy_ = proxy;
   if (bindings_) {
     bindings_->CallClientFunction("DevToolsAPI.frontendAPIAttached",
                                   nullptr, nullptr, nullptr);
@@ skipping 662 matching lines @@
 void DevToolsUIBindings::FrontendLoaded() {
   if (frontend_loaded_)
     return;
   frontend_loaded_ = true;
 
   // Call delegate first - it seeds importants bit of information.
   delegate_->OnLoadCompleted();
 
   AddDevToolsExtensionsToClient();
 }