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

third_party/WebKit/public/platform/media_in_product_help.mojom

Index: third_party/WebKit/public/platform/media_in_product_help.mojom
diff --git a/third_party/WebKit/public/platform/media_in_product_help.mojom b/third_party/WebKit/public/platform/media_in_product_help.mojom
new file mode 100644
index 0000000000000000000000000000000000000000..2321d3f59d98a73dcbceb0221cf6bb9f8b4f26fa
--- /dev/null
+++ b/third_party/WebKit/public/platform/media_in_product_help.mojom
@@ -0,0 +1,25 @@
+// 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.
+
+module blink.mojom;
+
+// Browser-side service used by the renderer for showing the InProductHelp UI
+// widget/popup for the media download button.
+interface MediaInProductHelpService {

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

We don't name mojo interfaces with Service suffixes anymore.

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

Done.

+  // The position of the button in the frame's local coordinate space, where the
+  // UI widget should be anchored.
+  // The request_id denotes the element making the request.
+  ShowInProductHelpWidget(int32 x, int32 y, int32 width, int32 height);

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

This should use a gfx.mojom.Rect.

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

Done.

+  
+  // Hide the widget currently being shown for this frame.
+  HideInProductHelpWidget();
+};
+
+// Renderer-side service to listen to notifications when the UI widget on the
+// browser is dismissed/removed.
+interface MediaInProductHelpDelegateService {
+  // Informs the renderer that the UI widget shown for this button in the
+  // browser was dismissed.
+  WidgetDismissed();

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

Could this message be a response to ShowInProductHelpWidget() instead? Then
HideInProductHelpWidget() could be replaced with the renderer closing the
connection before that response is sent.

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

For the initial request, yes. But the browser can dismiss the widget from any
other event after the response has been dispatched. Touching anywhere on the
screen for instance.
I'm not sure I understood this one. This hiding will be the result of a layout
change which removes the button from the page in the renderer.

Did you mean keeping the MediaInProductHelpPtr in LocalFrame for the duration
the renderer wants to show the UI and destroying it to close the connection and
using that as a notification to hide it in the browser instead of
HideInProductHelpWidget?

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

In that case, the browser could close the connection and rely on the renderer
observing the close.
I mean keeping the MediaInProductHelpPtr on one of the classes in
modules/media_controls and then each side can close the connection to indicate
that it wants the UI to be hidden.

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

Thanks for the inputs. Isolating the code to the controls and using connection
notification callbacks does simplify this a lot.

+};