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

third_party/WebKit/Source/core/frame/LocalFrame.cpp

Index: third_party/WebKit/Source/core/frame/LocalFrame.cpp
diff --git a/third_party/WebKit/Source/core/frame/LocalFrame.cpp b/third_party/WebKit/Source/core/frame/LocalFrame.cpp
index 68560d692093b4bbe2ab1ab902a56aa743f1ff3b..15d78bebfc61abc10467a3cf8e879d835f338a4a 100644
--- a/third_party/WebKit/Source/core/frame/LocalFrame.cpp
+++ b/third_party/WebKit/Source/core/frame/LocalFrame.cpp
@@ -54,6 +54,7 @@
 #include "core/frame/Settings.h"
 #include "core/frame/VisualViewport.h"
 #include "core/html/HTMLFrameElementBase.h"
+#include "core/html/HTMLMediaElement.h"
 #include "core/html/HTMLPlugInElement.h"
 #include "core/html/PluginDocument.h"
 #include "core/input/EventHandler.h"
@@ -79,6 +80,7 @@
 #include "core/probe/CoreProbes.h"
 #include "core/svg/SVGDocumentExtensions.h"
 #include "core/timing/Performance.h"
+#include "mojo/public/cpp/bindings/strong_binding.h"
 #include "platform/DragImage.h"
 #include "platform/Histogram.h"
 #include "platform/PluginScriptForbiddenScope.h"
@@ -106,6 +108,9 @@
 #include "public/platform/InterfaceRegistry.h"
 #include "public/platform/WebScreenInfo.h"
 #include "public/platform/WebURLRequest.h"
+#include "public/platform/media_in_product_help.mojom-blink.h"
+#include "services/service_manager/public/cpp/bind_source_info.h"
+#include "services/service_manager/public/cpp/interface_provider.h"
 #include "third_party/skia/include/core/SkImage.h"
 #include "third_party/skia/include/core/SkSurface.h"
 
@@ -272,6 +277,31 @@ FrameInitCallbackVector& GetInitializationVector() {
   return initialization_vector;
 }
 
+class MediaInProductHelpDelegateService
+    : public mojom::blink::MediaInProductHelpDelegateService {
+ public:
+  explicit MediaInProductHelpDelegateService(LocalFrame& frame)
+      : frame_(&frame) {}
+  ~MediaInProductHelpDelegateService() override = default;
+
+  // chrome::MediaInProductHelpDelegateService implementation.
+  void WidgetDismissed() override {
+    if (frame_)
+      frame_->NotifyInProductHelpDismissed();
+  }
+
+ private:
+  WeakPersistent<LocalFrame> frame_;
+};
+
+void CreateMediaInProductHelpDelegateService(
+    LocalFrame* frame,
+    mojom::blink::MediaInProductHelpDelegateServiceRequest request) {
+  mojo::MakeStrongBinding(
+      WTF::WrapUnique(new MediaInProductHelpDelegateService(*frame)),
+      std::move(request));
+}
+
 }  // namespace
 
 template class CORE_TEMPLATE_EXPORT Supplement<LocalFrame>;
@@ -382,6 +412,7 @@ DEFINE_TRACE(LocalFrame) {
   visitor->Trace(console_);
   visitor->Trace(input_method_controller_);
   visitor->Trace(frame_resource_coordinator_);
+  visitor->Trace(element_with_active_in_product_help_);
   Frame::Trace(visitor);
   Supplementable<LocalFrame>::Trace(visitor);
 }
@@ -1245,4 +1276,67 @@ void LocalFrame::SetViewportIntersectionFromParent(
   }
 }
 
+void LocalFrame::ShowDownloadMediaInProductHelp(HTMLMediaElement& elem) {

[Sam McNally, 2017/06/28 09:19:58]

Could this be handled within MediaControlDownloadButtonElement or
MediaControlsImpl? It doesn't feel like LocalFrame should need to know about
this. It seems to me that the browser is already enforcing one help widget per
WebContents so repeating that here doesn't seem necessary. If the delegate
interface is replaced with a response then the tracking of the element isn't
necessary either.

[Khushal, 2017/06/28 22:28:46]

The element had to be tracked at some place which hears about Layout changes to
send the updated position to the browser.

[Sam McNally, 2017/07/03 09:45:40]

MediaControlsImpl should be able to observe layout via its ResizeObserver.
Having every interested party add some code in LocalFrame for observing layout
doesn't seem very scalable. I'm not sure this captures all changes that might
matter, e.g. CSS visibility changes or scrolling, but I don't think observing
layout in LocalFrame would either.

[Khushal, 2017/07/07 04:18:13]

The ResizeObserver only hears about size changes in the video element, so it
captures less than what a Layout event on the Frame would have. But you're right
that it still ignores multiple changes (scrolling, etc.). Since we dismiss the
UI on any user interaction, in most cases the position of the button remains
static. I've moved the code for sending the rect to MediaControlsImpl and
restricted the update to dismissing the UI when the controls or the button are
hidden.

+  if (!GetSettings() || !GetSettings()->GetMediaDownloadInProductHelpEnabled())
+    return;
+
+  if (element_with_active_in_product_help_ ||
+      media_in_product_help_shown_for_frame_)
+    return;
+
+  if (!Client())
+    return;
+
+  // Add the service to know when this widget is dismissed.
+  GetInterfaceRegistry()->AddInterface(WTF::Bind(
+      &CreateMediaInProductHelpDelegateService, WrapWeakPersistent(this)));
+
+  element_with_active_in_product_help_ = &elem;
+  media_in_product_help_shown_for_frame_ = true;
+}
+
+bool LocalFrame::IsDownloadMediaInProductHelpVisibleForElement(
+    HTMLMediaElement& elem) {
+  return element_with_active_in_product_help_ &&
+         *element_with_active_in_product_help_ == elem;
+}
+
+void LocalFrame::NotifyMediaControlsHidden(HTMLMediaElement& elem) {
+  if (!element_with_active_in_product_help_ ||
+      *element_with_active_in_product_help_ != elem || !Client())
+    return;
+
+  mojom::blink::MediaInProductHelpServicePtr service;
+  Client()->GetInterfaceProvider()->GetInterface(mojo::MakeRequest(&service));
+  service->HideInProductHelpWidget();
+}
+
+void LocalFrame::LayoutUpdated() {
+  if (!element_with_active_in_product_help_ || !Client())
+    return;
+
+  IntRect button_rect;
+  if (!element_with_active_in_product_help_->GetMediaControls()
+           ->GetDownloadButtonRect(button_rect)) {
+    mojom::blink::MediaInProductHelpServicePtr service;
+    Client()->GetInterfaceProvider()->GetInterface(mojo::MakeRequest(&service));
+    service->HideInProductHelpWidget();
+    return;
+  }
+
+  mojom::blink::MediaInProductHelpServicePtr service;
+  Client()->GetInterfaceProvider()->GetInterface(mojo::MakeRequest(&service));
+  service->ShowInProductHelpWidget(button_rect.X(), button_rect.Y(),
+                                   button_rect.Width(), button_rect.Height());
+}
+
+void LocalFrame::NotifyInProductHelpDismissed() {
+  if (element_with_active_in_product_help_ &&
+      element_with_active_in_product_help_->GetMediaControls()) {
+    element_with_active_in_product_help_->GetMediaControls()
+        ->InProductHelpDisabled();
+  }
+  element_with_active_in_product_help_ = nullptr;
+}
+
 }  // namespace blink