Add a download button to the media player

third_party/WebKit/Source/core/html/shadow/MediaControlElements.h

Index: third_party/WebKit/Source/core/html/shadow/MediaControlElements.h
diff --git a/third_party/WebKit/Source/core/html/shadow/MediaControlElements.h b/third_party/WebKit/Source/core/html/shadow/MediaControlElements.h
index f0652ad7b8717209912723009fe7b11782ad1d54..c7e4633692f97df38f610d0c79a190c250552633 100644
--- a/third_party/WebKit/Source/core/html/shadow/MediaControlElements.h
+++ b/third_party/WebKit/Source/core/html/shadow/MediaControlElements.h
@@ -215,6 +215,23 @@ private:
 };
 
 // ----------------------------
+// Represents a button that allows users to download media if the file is
+// downloadable.
+class MediaControlDownloadButtonElement final : public MediaControlInputElement {
+public:
+    static MediaControlDownloadButtonElement* create(MediaControls&, Document*);
+
+    WebLocalizedString::Name getOverflowStringName() override;
+
+    // Returns true if the download button should be shown. We should
+    // show the button for only non-MSE, non-EME, and non-MediaStream content.
+    bool shouldDisplayDownloadButton();
+
+private:
+    explicit MediaControlDownloadButtonElement(MediaControls&);
+
+    void defaultEventHandler(Event*) override;
+};
 
 class MediaControlTimelineElement final : public MediaControlInputElement {
 public: