Make sure gin Handles exist before using them

content/shell/renderer/test_runner/text_input_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/shell/renderer/test_runner/text_input_controller.h"
 
 #include "gin/arguments.h"
 #include "gin/handle.h"
 #include "gin/object_template_builder.h"
 #include "gin/wrappable.h"
@@ skipping 50 matching lines @@
   v8::Isolate* isolate = blink::mainThreadIsolate();
   v8::HandleScope handle_scope(isolate);
   v8::Handle<v8::Context> context = frame->mainWorldScriptContext();
   if (context.IsEmpty())
     return;
 
   v8::Context::Scope context_scope(context);
 
   gin::Handle<TextInputControllerBindings> bindings =
       gin::CreateHandle(isolate, new TextInputControllerBindings(controller));
+  if (bindings.IsEmpty())
+    return;
   v8::Handle<v8::Object> global = context->Global();
   global->Set(gin::StringToV8(isolate, "textInputController"), bindings.ToV8());
 }
 
 TextInputControllerBindings::TextInputControllerBindings(
     base::WeakPtr<TextInputController> controller)
     : controller_(controller) {}
 
 TextInputControllerBindings::~TextInputControllerBindings() {}
 
@@ skipping 172 matching lines @@
   key_down.windowsKeyCode = 0xE5;  // VKEY_PROCESSKEY
   key_down.setKeyIdentifierFromWindowsKeyCode();
   view_->handleInputEvent(key_down);
 
   blink::WebVector<blink::WebCompositionUnderline> underlines;
   blink::WebString web_text(blink::WebString::fromUTF8(text));
   view_->setComposition(web_text, underlines, 0, web_text.length());
 }
 
 }  // namespace content