[chromecast] Enable Mojo javascript bindings for cast_shell

chromecast/renderer/cast_gin_runner.h

Index: chromecast/renderer/cast_gin_runner.h
diff --git a/chromecast/renderer/cast_gin_runner.h b/chromecast/renderer/cast_gin_runner.h
new file mode 100644
index 0000000000000000000000000000000000000000..9865051d1c27685944b39c9286594a990cd029b9
--- /dev/null
+++ b/chromecast/renderer/cast_gin_runner.h
@@ -0,0 +1,61 @@
+// Copyright 2016 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.
+
+#ifndef CHROMECAST_RENDERER_CAST_GIN_RUNNER_H_
+#define CHROMECAST_RENDERER_CAST_GIN_RUNNER_H_
+
+#include "base/macros.h"
+#include "base/supports_user_data.h"
+#include "content/public/renderer/render_frame_observer.h"
+#include "gin/runner.h"
+
+namespace blink {
+class WebFrame;
+}
+
+namespace chromecast {
+namespace shell {
+
+extern const char kCastContextData[];
+
+// Implementation of gin::Runner that forwards Runner functions to WebFrame.
+class CastGinRunner : public gin::Runner,
+                      public base::SupportsUserData::Data,
+                      public content::RenderFrameObserver {
+ public:
+  // Does not take ownership of ContextHolder.
+  CastGinRunner(content::RenderFrame* render_frame,
+                blink::WebFrame* frame,
+                gin::ContextHolder* context_holder);
+  ~CastGinRunner() override {}
+
+  // gin:Runner implementation:
+  void Run(const std::string& source,
+           const std::string& resource_name) override;
+  v8::Local<v8::Value> Call(v8::Local<v8::Function> function,
+                            v8::Local<v8::Value> receiver,
+                            int argc,
+                            v8::Local<v8::Value> argv[]) override;
+  gin::ContextHolder* GetContextHolder() override;
+
+  // content::RenderFrameObserver implementation:
+  void WillReleaseScriptContext(v8::Local<v8::Context> context,
+                                int world_id) override;
+  void DidClearWindowObject() override;
+  void OnDestruct() override;
+
+ private:
+  // Frame to execute script in.
+  blink::WebFrame* const frame_;
+
+  // Created by blink bindings to V8.
+  gin::ContextHolder* const context_holder_;
+
+  DISALLOW_COPY_AND_ASSIGN(CastGinRunner);
+};
+
+}  // namespace shell
+}  // namespace chromecast
+
+#endif  // CHROMECAST_RENDERER_CAST_GIN_RUNNER_H_