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

third_party/WebKit/Source/modules/media_controls/MediaControlsImpl.h

Index: third_party/WebKit/Source/modules/media_controls/MediaControlsImpl.h
diff --git a/third_party/WebKit/Source/modules/media_controls/MediaControlsImpl.h b/third_party/WebKit/Source/modules/media_controls/MediaControlsImpl.h
index c8bba03406999ebcf2a926da86f0cb5d7b5ef120..2163cc019e7fd3bf84a1e2e7018ec9c265d49e03 100644
--- a/third_party/WebKit/Source/modules/media_controls/MediaControlsImpl.h
+++ b/third_party/WebKit/Source/modules/media_controls/MediaControlsImpl.h
@@ -98,6 +98,8 @@ class MODULES_EXPORT MediaControlsImpl final : public HTMLDivElement,
     // There is no update because only the overlay is expected to change.
     RefreshCastButtonVisibilityWithoutUpdate();
   }
+  bool GetDownloadButtonRect(IntRect&) override;
+  void IPHDisabled() override;
   Document& OwnerDocument() { return GetDocument(); }
 
   // Called by the fullscreen buttons to toggle fulllscreen on/off.
@@ -120,6 +122,8 @@ class MODULES_EXPORT MediaControlsImpl final : public HTMLDivElement,
   void EndScrubbing();
   void UpdateCurrentTimeDisplay();
 
+  void MaybeDispatchDownloadIPHTrigger();
+
   DECLARE_VIRTUAL_TRACE();
 
  private:
@@ -257,6 +261,14 @@ class MODULES_EXPORT MediaControlsImpl final : public HTMLDivElement,
   IntSize size_;
 
   bool keep_showing_until_timer_fires_ : 1;
+
+  // Set to true when a IPH for the download button on the controls is being
+  // displayed.
+  bool iph_active_ = false;
+
+  // Set to true after the IPH trigger for an element has been observed. This
+  // ensures that the trigger for an element is observed only once.
+  bool iph_trigger_observed_ = false;
 };
 
 DEFINE_ELEMENT_TYPE_CASTS(MediaControlsImpl, IsMediaControls());