[DevTools] Only create DevToolsAgent for local main frame.

content/renderer/render_view_impl.cc

Index: content/renderer/render_view_impl.cc
diff --git a/content/renderer/render_view_impl.cc b/content/renderer/render_view_impl.cc
index 02ed7244a4193f196df38a3488c8926478ece467..eecfa02094a668f7b8ce1138b6f8c6a2b81674a6 100644
--- a/content/renderer/render_view_impl.cc
+++ b/content/renderer/render_view_impl.cc
@@ -777,10 +777,12 @@ void RenderViewImpl::Initialize(const ViewMsg_New_Params& params,
 
   // The next group of objects all implement RenderViewObserver, so are deleted
   // along with the RenderView automatically.
-  devtools_agent_ = new DevToolsAgent(main_render_frame_.get());
-  if (RenderWidgetCompositor* rwc = compositor()) {
-    webview()->devToolsAgent()->setLayerTreeId(rwc->GetLayerTreeId());
+  if (!proxy) {
+    devtools_agent_ = new DevToolsAgent(main_render_frame_.get());
+    if (RenderWidgetCompositor* rwc = compositor())
+      webview()->devToolsAgent()->setLayerTreeId(rwc->GetLayerTreeId());
   }
+
   mouse_lock_dispatcher_ = new RenderViewMouseLockDispatcher(this);
 
   history_controller_.reset(new HistoryController(this));