chrome/blink: Add functionality for in-product help for media elements.

chrome/browser/android/media_iph_manager.h

+// Copyright 2017 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 CHROME_BROWSER_ANDROID_MEDIA_IPH_MANAGER_H_
+#define CHROME_BROWSER_ANDROID_MEDIA_IPH_MANAGER_H_
+
+#include "base/memory/weak_ptr.h"
+#include "chrome/common/media_iph.mojom.h"
+#include "content/public/browser/web_contents_observer.h"
+#include "services/service_manager/public/cpp/binder_registry.h"
+
+class MediaIPHManagerClient {
+ public:
+  ~MediaIPHManagerClient() {}
+
+  // Request to show the IPH for media download. Returns true iff the IPH can
+  // be shown.
+  virtual bool ShowMediaDownloadIPH() = 0;
+
+  // Updates the position of the IPH widget. |rect_in_frame| provides the
+  // position of the widget in the space of the renderer's main frame.
+  virtual void UpdateMediaDownloadIPHPosition(

[chrishtr, 2017/06/23 00:39:44]

You can remove this method and pass the rect to ShowMediaDownloadIPH.

[Khushal, 2017/06/28 05:32:38]

Done.

+      const gfx::Rect& rect_in_frame) = 0;
+
+  // Request to dismiss the IPH widget. This request must be acknowledged using
+  // MediaIPHManager::WidgetDismissed once the widget is removed.
+  virtual void DismissMediaDownloadIPH() = 0;
+};
+
+class MediaIPHManager : public content::WebContentsObserver {
+ public:
+  MediaIPHManager(content::WebContents* web_contents,
+                  MediaIPHManagerClient* client);
+  ~MediaIPHManager() override;
+
+  // Notifies when the IPH widget requested from the client is removed.
+  void WidgetDismissed();
+
+  // content::WebContentsObserver implementation.
+  // TODO(khushalsagar): Listen to navigations/process crash to dismiss the
+  // widget in the browser.
+  void RenderFrameCreated(content::RenderFrameHost* render_frame_host) override;
+  void RenderFrameDeleted(content::RenderFrameHost* render_frame_host) override;
+
+ private:
+  class MediaIPHService;
+
+  // Methods used by MediaIPHService to plumb notifications from the renderer.
+  void ShowIPHWidget(content::RenderFrameHost* render_frame_host,
+                     const gfx::Rect& rect_in_main_frame,
+                     bool new_request);
+  void HideIPHWidget(content::RenderFrameHost* render_frame_host);
+
+  // Creates the mojo service exposed to the renderer.
+  void CreateIPHService(content::RenderFrameHost* render_frame_host,
+                        const service_manager::BindSourceInfo& source_info,
+                        chrome::mojom::MediaIPHServiceRequest request);
+  void DismissUI();
+
+  content::RenderFrameHost* active_render_frame_host_ = nullptr;
+  MediaIPHManagerClient* client_;
+  base::WeakPtrFactory<MediaIPHManager> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(MediaIPHManager);
+};
+
+#endif  // CHROME_BROWSER_ANDROID_MEDIA_IPH_MANAGER_H_