Add download button to MediaDocument on Android.

content/child/runtime_features.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/child/runtime_features.h"
 
 #include <vector>
 
 #include "base/command_line.h"
 #include "base/feature_list.h"
@@ skipping 159 matching lines @@
 
   if (base::FeatureList::IsEnabled(features::kScrollAnchoring))
     WebRuntimeFeatures::enableScrollAnchoring(true);
 
   if (command_line.HasSwitch(switches::kEnableSlimmingPaintV2))
     WebRuntimeFeatures::enableSlimmingPaintV2(true);
 
   if (base::FeatureList::IsEnabled(features::kRenderingPipelineThrottling))
     WebRuntimeFeatures::enableRenderingPipelineThrottling(true);
 
+  if (command_line.HasSwitch(switches::kEnableMediaDocumentDownloadButton))
+    WebRuntimeFeatures::enableMediaDocumentDownloadButton(true);
+
   // Enable explicitly enabled features, and then disable explicitly disabled
   // ones.
   if (command_line.HasSwitch(switches::kEnableBlinkFeatures)) {
     std::vector<std::string> enabled_features = base::SplitString(
         command_line.GetSwitchValueASCII(switches::kEnableBlinkFeatures),
         ",", base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);
     for (const std::string& feature : enabled_features)
       WebRuntimeFeatures::enableFeatureFromString(feature, true);
   }
   if (command_line.HasSwitch(switches::kDisableBlinkFeatures)) {
     std::vector<std::string> disabled_features = base::SplitString(
         command_line.GetSwitchValueASCII(switches::kDisableBlinkFeatures),
         ",", base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);
     for (const std::string& feature : disabled_features)
       WebRuntimeFeatures::enableFeatureFromString(feature, false);
   }
 }
 
 }  // namespace content