[App Shell] Add dev tools for debugging

apps/shell/browser/shell_browser_main_parts.cc

Index: apps/shell/browser/shell_browser_main_parts.cc
diff --git a/apps/shell/browser/shell_browser_main_parts.cc b/apps/shell/browser/shell_browser_main_parts.cc
index 090d97f3cd535569686c951a8ce5895deae3015e..f6c5a0bce1a28a3c517f51282f3a68ee849b4099 100644
--- a/apps/shell/browser/shell_browser_main_parts.cc
+++ b/apps/shell/browser/shell_browser_main_parts.cc
@@ -15,6 +15,7 @@
 #include "base/run_loop.h"
 #include "components/browser_context_keyed_service/browser_context_dependency_manager.h"
 #include "content/public/common/result_codes.h"
+#include "content/shell/browser/shell_devtools_delegate.h"
 #include "content/shell/browser/shell_net_log.h"
 #include "extensions/browser/extension_system.h"
 #include "extensions/browser/renderer_startup_helper.h"
@@ -116,6 +117,9 @@ void ShellBrowserMainParts::PreMainMessageLoopRun() {
   BrowserContextDependencyManager::GetInstance()->CreateBrowserContextServices(
       browser_context_.get());
 
+  devtools_delegate_.reset(
+      new content::ShellDevToolsDelegate(browser_context_.get()));
+
   CreateRootWindow();
   CreateViewsDelegate();
 
@@ -142,6 +146,7 @@ bool ShellBrowserMainParts::MainMessageLoopRun(int* result_code)  {
 }
 
 void ShellBrowserMainParts::PostMainMessageLoopRun() {
+  devtools_delegate_->Stop();
   DestroyViewsDelegate();
   DestroyRootWindow();
   BrowserContextDependencyManager::GetInstance()->DestroyBrowserContextServices(