Don't show media controls download button on local files.

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

 /*
  * Copyright (C) 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 635 matching lines @@
 
 WebLocalizedString::Name MediaControlDownloadButtonElement::getOverflowStringName()
 {
     return WebLocalizedString::OverflowMenuDownload;
 }
 
 bool MediaControlDownloadButtonElement::shouldDisplayDownloadButton()
 {
     const KURL& url = mediaElement().currentSrc();
 
-    if (!url.isNull() && !url.isEmpty() && !HTMLMediaElement::isMediaStreamURL(url.getString()) && !url.protocolIs("blob") && !HTMLMediaSource::lookup(url)) {
-        return true;
-    }
-    return false;
+    // URLs that lead to nowhere are ignored.
+    if (url.isNull() || url.isEmpty())
+        return false;
+
+    // Local files and blobs should not have a download button.
+    if (url.isLocalFile() || url.protocolIs("blob"))
+        return false;
+
+    // MediaStream can't be downloaded.
+    if (HTMLMediaElement::isMediaStreamURL(url.getString()))
+        return false;
+
+    // MediaSource can't be downloaded.
+    if (HTMLMediaSource::lookup(url))
+        return false;
+
+    return true;
 }
 
 void MediaControlDownloadButtonElement::defaultEventHandler(Event* event)
 {
     const KURL& url = mediaElement().currentSrc();
     if (event->type() == EventTypeNames::click && !(url.isNull() || url.isEmpty())) {
         Platform::current()->recordAction(UserMetricsAction("Media.Controls.Download"));
         if (!m_anchor) {
             HTMLAnchorElement* anchor = HTMLAnchorElement::create(document());
             anchor->setAttribute(HTMLNames::downloadAttr, "");
@@ skipping 325 matching lines @@
 }
 
 MediaControlCurrentTimeDisplayElement* MediaControlCurrentTimeDisplayElement::create(MediaControls& mediaControls)
 {
     MediaControlCurrentTimeDisplayElement* element = new MediaControlCurrentTimeDisplayElement(mediaControls);
     element->setShadowPseudoId(AtomicString("-webkit-media-controls-current-time-display"));
     return element;
 }
 
 } // namespace blink