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

third_party/WebKit/Source/modules/media_controls/elements/MediaControlDownloadButtonElement.cpp

Index: third_party/WebKit/Source/modules/media_controls/elements/MediaControlDownloadButtonElement.cpp
diff --git a/third_party/WebKit/Source/modules/media_controls/elements/MediaControlDownloadButtonElement.cpp b/third_party/WebKit/Source/modules/media_controls/elements/MediaControlDownloadButtonElement.cpp
index 2007c5d81496f008d9a3228e482bb144f32c404f..61130cbdf15553698dcdcd0f923cce4620615eda 100644
--- a/third_party/WebKit/Source/modules/media_controls/elements/MediaControlDownloadButtonElement.cpp
+++ b/third_party/WebKit/Source/modules/media_controls/elements/MediaControlDownloadButtonElement.cpp
@@ -6,6 +6,7 @@
 
 #include "core/InputTypeNames.h"
 #include "core/events/Event.h"
+#include "core/frame/LocalFrameClient.h"
 #include "core/frame/Settings.h"
 #include "core/html/HTMLAnchorElement.h"
 #include "core/html/HTMLMediaElement.h"
@@ -14,7 +15,9 @@
 #include "core/page/Page.h"
 #include "modules/media_controls/MediaControlsImpl.h"
 #include "platform/Histogram.h"
+#include "platform/wtf/Functional.h"
 #include "public/platform/Platform.h"
+#include "services/service_manager/public/cpp/interface_provider.h"
 
 namespace blink {
 
@@ -91,11 +94,14 @@ void MediaControlDownloadButtonElement::SetIsWanted(bool wanted) {
   if (!IsWanted())
     return;
 
-  DCHECK(IsWanted());
   if (!show_use_counted_) {
     show_use_counted_ = true;
     RecordMetrics(DownloadActionMetrics::kShown);
   }
+
+  // If the button is wanted, show IPH if possible.
+  MaybeDispatchInProductHelpTrigger();
+  UpdateInProductHelpState();
 }
 
 DEFINE_TRACE(MediaControlDownloadButtonElement) {
@@ -132,4 +138,53 @@ void MediaControlDownloadButtonElement::RecordMetrics(
   download_action_histogram.Count(static_cast<int>(metric));
 }
 
+void MediaControlDownloadButtonElement::MaybeDispatchInProductHelpTrigger() {

[mlamouri (slow - plz ping), 2017/07/13 21:14:27]

For what I can see, this setting up the mojo pipe. Is it triggering anything?

[Khushal, 2017/07/17 17:52:21]

MaybeShow would have called UpdateInProductHelpState which triggers showing. Now
this triggers it directly.

+  if (!media_download_in_product_trigger_observed_ && IsWanted() &&
+      !MediaElement().paused() && MediaElement().GetDocument().GetSettings() &&
+      MediaElement()
+          .GetDocument()
+          .GetSettings()
+          ->GetMediaDownloadInProductHelpEnabled()) {

[mlamouri (slow - plz ping), 2017/07/13 21:14:27]

For readability, can you do an early return?

[Khushal, 2017/07/17 17:52:21]

Done.

+    DCHECK(!media_in_product_help_);
+
+    media_download_in_product_trigger_observed_ = true;
+    media_in_product_help_ =
+        WTF::MakeUnique<mojom::blink::MediaInProductHelpPtr>();
+    MediaElement()
+        .GetDocument()
+        .GetFrame()

[mlamouri (slow - plz ping), 2017/07/13 21:14:27]

Can you check that `GetFrame()` doesn't return `nullptr`?

[Khushal, 2017/07/17 17:52:21]

Done.

+        ->Client()
+        ->GetInterfaceProvider()
+        ->GetInterface(mojo::MakeRequest(media_in_product_help_.get()));
+    media_in_product_help_->set_connection_error_handler(
+        ConvertToBaseCallback(WTF::Bind(
+            &MediaControlDownloadButtonElement::DismissDownloadInProductHelp,
+            WrapWeakPersistent(this))));
+    GetMediaControls().MaybeShow();

[mlamouri (slow - plz ping), 2017/07/13 21:14:27]

Does that mean that when a download button will be added, we will show the
controls if they are not already showing?

[Khushal, 2017/07/17 17:52:21]

I updated the code to take the CanShow aspect into account, but yes, if we can
show the controls and a download button is added, this will make them visible.

+  }
+}
+
+void MediaControlDownloadButtonElement::UpdateInProductHelpState() {

[mlamouri (slow - plz ping), 2017/07/13 21:14:27]

Isn't this method actually triggering the UI?

[Khushal, 2017/07/17 17:52:21]

Restructured to move this into MaybeDispatchInProductHelpTrigger.

+  if (!media_in_product_help_)
+    return;
+
+  if (static_cast<MediaControlsImpl&>(GetMediaControls()).IsVisible() &&
+      IsWanted()) {
+    (*media_in_product_help_)
+        ->ShowInProductHelpWidget(VisibleBoundsInVisualViewport());
+    return;
+  }
+
+  DismissDownloadInProductHelp();
+}
+
+void MediaControlDownloadButtonElement::DismissDownloadInProductHelp() {
+  media_in_product_help_.reset();
+  static_cast<MediaControlsImpl&>(GetMediaControls()).HideControlsIfNecessary();
+}
+
+bool MediaControlDownloadButtonElement::IsShowingInProductHelp() const {
+  return !!media_in_product_help_;
+}
+
 }  // namespace blink