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

chrome/browser/android/media_in_product_help_manager.cc

+// 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.
+
+#include "chrome/browser/android/media_in_product_help_manager.h"
+
+#include "base/memory/ptr_util.h"
+#include "base/optional.h"
+#include "content/public/browser/navigation_handle.h"
+#include "content/public/browser/render_frame_host.h"
+#include "content/public/browser/render_widget_host_view.h"
+#include "mojo/public/cpp/bindings/strong_binding.h"
+#include "services/service_manager/public/cpp/bind_source_info.h"
+#include "services/service_manager/public/cpp/interface_provider.h"
+
+namespace {
+
+void SendDismissUIToRenderer(content::RenderFrameHost* render_frame_host) {
+  blink::mojom::MediaInProductHelpDelegatePtr delegate_service;
+  render_frame_host->GetRemoteInterfaces()->GetInterface(&delegate_service);
+  delegate_service->WidgetDismissed();
+}
+
+}  // namespace
+
+class MediaInProductHelpManager::MediaInProductHelp
+    : public blink::mojom::MediaInProductHelp {
+ public:
+  MediaInProductHelp(content::RenderFrameHost* render_frame_host,
+                     MediaInProductHelpManager* manager)
+      : render_frame_host_(render_frame_host), manager_(manager) {
+    DCHECK(render_frame_host_);
+    DCHECK(manager_);
+  }
+  ~MediaInProductHelp() override = default;
+
+  // blink::mojom::MediaPromoUI implementation.
+  void ShowInProductHelpWidget(const gfx::Rect& rect) override {
+    manager_->ShowInProductHelpWidget(render_frame_host_, rect);
+  }
+
+  void HideInProductHelpWidget() override {
+    manager_->HideInProductHelpWidget(render_frame_host_);
+  }
+
+ private:
+  content::RenderFrameHost* render_frame_host_;
+  MediaInProductHelpManager* manager_;

[nyquist, 2017/06/29 02:10:23]

Nit: Could you write a comment about lifetime / ownership of these raw pointers?

[Khushal, 2017/07/07 04:18:14]

Done.

+};
+
+MediaInProductHelpManager::MediaInProductHelpManager(
+    content::WebContents* web_contents,
+    MediaInProductHelpManagerClient* client)
+    : WebContentsObserver(web_contents), client_(client), weak_factory_(this) {
+  DCHECK(client_);
+}
+
+MediaInProductHelpManager::~MediaInProductHelpManager() {
+  if (active_render_frame_host_) {
+    client_->DismissMediaDownloadInProductHelp();

[nyquist, 2017/06/29 02:10:23]

In the API description, it's stated that a call to this method requires a call
to MediaInProductHelpManager::WidgetDismissed(), but in this case, that'd be
after |this| is destructed?

Would the DCHECK(media_iph_manager_) in
TabAndroid::DownloadMediaInProductHelpDismissed hit?

[Khushal, 2017/07/07 04:18:14]

It should happen in the same call stack. The call to the client synchronously
dismisses the widget and informs this class.
I was hitting that DCHECK in the case of shutdown. Didn't realize that the UI
had to be cleaned up in Tab.destroy, before the native WebContents is destroyed.

+  }
+}
+
+void MediaInProductHelpManager::WidgetDismissed() {
+  DCHECK(active_render_frame_host_);
+
+  SendDismissUIToRenderer(active_render_frame_host_);
+  active_render_frame_host_ = nullptr;
+}
+
+void MediaInProductHelpManager::RenderFrameCreated(
+    content::RenderFrameHost* render_frame_host) {
+  // Register the bridge service for the renderer to request showing the UI.
+  render_frame_host->GetInterfaceRegistry()->AddInterface(
+      base::Bind(&MediaInProductHelpManager::CreateInProductHelpService,
+                 weak_factory_.GetWeakPtr(), render_frame_host));
+}
+
+void MediaInProductHelpManager::RenderFrameDeleted(
+    content::RenderFrameHost* render_frame_host) {
+  if (active_render_frame_host_ != render_frame_host)
+    return;
+  client_->DismissMediaDownloadInProductHelp();
+}
+
+void MediaInProductHelpManager::CreateInProductHelpService(
+    content::RenderFrameHost* render_frame_host,
+    const service_manager::BindSourceInfo& source_info,
+    blink::mojom::MediaInProductHelpRequest request) {
+  mojo::MakeStrongBinding(
+      base::MakeUnique<MediaInProductHelp>(render_frame_host, this),
+      std::move(request));
+}
+
+void MediaInProductHelpManager::ShowInProductHelpWidget(
+    content::RenderFrameHost* render_frame_host,
+    const gfx::Rect& rect_in_main_frame) {
+  if (active_render_frame_host_ &&
+      active_render_frame_host_ != render_frame_host) {
+    // If we are currently showing the UI for another frame, inform the
+    // requesting frame that the widget can not be shown.
+    SendDismissUIToRenderer(render_frame_host);
+    return;
+  }
+
+  active_render_frame_host_ = render_frame_host;
+  client_->ShowMediaDownloadInProductHelp(rect_in_main_frame);
+}
+
+void MediaInProductHelpManager::HideInProductHelpWidget(
+    content::RenderFrameHost* render_frame_host) {
+  // We might have dismissed the widget for this frame already.
+  if (active_render_frame_host_ != render_frame_host)
+    return;
+  client_->DismissMediaDownloadInProductHelp();
+}