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

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

Index: third_party/WebKit/Source/modules/media_controls/elements/MediaControlDownloadButtonElement.h
diff --git a/third_party/WebKit/Source/modules/media_controls/elements/MediaControlDownloadButtonElement.h b/third_party/WebKit/Source/modules/media_controls/elements/MediaControlDownloadButtonElement.h
index da1f7e08f9f7f6a3100155d5584ace7ce67f5ca9..907849269a90766990f61abbe97d163b56140da4 100644
--- a/third_party/WebKit/Source/modules/media_controls/elements/MediaControlDownloadButtonElement.h
+++ b/third_party/WebKit/Source/modules/media_controls/elements/MediaControlDownloadButtonElement.h
@@ -6,6 +6,7 @@
 #define MediaControlDownloadButtonElement_h
 
 #include "core/html/shadow/MediaControlElementTypes.h"
+#include "public/platform/media_in_product_help.mojom-blink.h"
 
 namespace blink {
 
@@ -21,6 +22,10 @@ class MediaControlDownloadButtonElement final
   // show the button for only non-MSE, non-EME, and non-MediaStream content.
   bool ShouldDisplayDownloadButton();
 
+  void UpdateInProductHelpState();
+  void MaybeDispatchInProductHelpTrigger();
+  bool IsShowingInProductHelp() const;
+
   // MediaControlInputElement overrides.
   // TODO(mlamouri): add WillRespondToMouseClickEvents
   WebLocalizedString::Name GetOverflowStringName() override;
@@ -41,6 +46,7 @@ class MediaControlDownloadButtonElement final
   void DefaultEventHandler(Event*) override;
 
   void RecordMetrics(DownloadActionMetrics);
+  void DismissDownloadInProductHelp();
 
   // Points to an anchor element that contains the URL of the media file.
   Member<HTMLAnchorElement> anchor_;
@@ -49,6 +55,9 @@ class MediaControlDownloadButtonElement final
   // for the same media element.
   bool click_use_counted_ = false;
   bool show_use_counted_ = false;
+
+  std::unique_ptr<mojom::blink::MediaInProductHelpPtr> media_in_product_help_;
+  bool media_download_in_product_trigger_observed_ = false;
 };
 
 }  // namespace blink