Fix nullptr dereference in MojoBindingsController

content/renderer/mojo_bindings_controller.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 "content/renderer/mojo_bindings_controller.h"
 
 #include "content/common/view_messages.h"
 #include "content/public/renderer/render_frame.h"
 #include "content/public/renderer/render_view.h"
 #include "content/renderer/mojo_context_state.h"
@@ skipping 20 matching lines @@
     : RenderFrameObserver(render_frame),
       RenderFrameObserverTracker<MojoBindingsController>(render_frame),
       for_layout_tests_(for_layout_tests) {}
 
 MojoBindingsController::~MojoBindingsController() {
 }
 
 void MojoBindingsController::CreateContextState() {
   v8::HandleScope handle_scope(blink::mainThreadIsolate());
   blink::WebLocalFrame* frame = render_frame()->GetWebFrame();
+  if (!frame)
+    return;
   v8::Local<v8::Context> context = frame->mainWorldScriptContext();
   gin::PerContextData* context_data = gin::PerContextData::From(context);
   MojoContextStateData* data = new MojoContextStateData;
   data->state.reset(new MojoContextState(frame, context, for_layout_tests_));
   context_data->SetUserData(kMojoContextStateKey, data);
 }
 
 void MojoBindingsController::DestroyContextState(
     v8::Local<v8::Context> context) {
   gin::PerContextData* context_data = gin::PerContextData::From(context);
@@ skipping 45 matching lines @@
 
   v8::HandleScope handle_scope(blink::mainThreadIsolate());
   DestroyContextState(render_frame()->GetWebFrame()->mainWorldScriptContext());
 }
 
 void MojoBindingsController::OnDestruct() {
   delete this;
 }
 
 }  // namespace content