[Contextual Search] Add Mojo-enabled API component.

components/contextual_search/overlay_js_render_frame_observer.h

+// Copyright 2015 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 COMPONENTS_CONTEXTUAL_SEARCH_OVERLAY_JS_RENDER_FRAME_OBSERVER_H_
+#define COMPONENTS_CONTEXTUAL_SEARCH_OVERLAY_JS_RENDER_FRAME_OBSERVER_H_
+
+#include "base/memory/weak_ptr.h"
+#include "components/contextual_search/overlay_page_notifier_service.mojom.h"
+#include "content/public/renderer/render_frame.h"
+#include "content/public/renderer/render_frame_observer.h"
+#include "third_party/WebKit/public/web/WebLocalFrame.h"
+#include "v8/include/v8.h"
+
+namespace contextual_search {
+
+// OverlayJsRenderFrame observer waits for a page to be loaded and then
+// tries to connect to a mojo service hosted in the browser process. The
+// service will tell this render process if the current page is presented
+// in an overlay panel.
+class OverlayJsRenderFrameObserver : public content::RenderFrameObserver {
+ public:
+  OverlayJsRenderFrameObserver(content::RenderFrame* render_frame);
+  ~OverlayJsRenderFrameObserver() override;
+
+  // RenderFrameObserver implementation.
+  void DidStartProvisionalLoad() override;
+  void DidCreateNewDocument() override;
+  void DidFinishLoad() override;
+
+  // Flag the current page as a contextual search overlay.
+  void SetIsContextualSearchOverlay();
+
+ private:
+  // Add the mojo service to a RenderFrame's service registry.
+  void RegisterMojoService();
+  void CreateOverlayPageNotifierService(
+      mojo::InterfaceRequest<OverlayPageNotifierService> request);
+
+  // Track if the current page is presented in the contextual search overlay.
+  bool is_contextual_search_overlay_;
+
+  base::WeakPtrFactory<OverlayJsRenderFrameObserver> weak_factory_;
+};
+
+}  // namespace contextual_search
+
+#endif  // COMPONENTS_CONTEXTUAL_SEARCH_OVERLAY_JS_RENDER_FRAME_OBSERVER_H_