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

components/feature_engagement_tracker/public/feature_constants.h

 // Copyright 2017 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.
 
 #ifndef COMPONENTS_FEATURE_ENGAGEMENT_TRACKER_PUBLIC_FEATURE_CONSTANTS_H_
 #define COMPONENTS_FEATURE_ENGAGEMENT_TRACKER_PUBLIC_FEATURE_CONSTANTS_H_
 
 #include "base/feature_list.h"
 #include "build/build_config.h"
 
 namespace feature_engagement_tracker {
 
 // A feature for enabling a demonstration mode for In-Product Help.
 extern const base::Feature kIPHDemoMode;
 
 // A feature to ensure all arrays can contain at least one feature.
 extern const base::Feature kIPHDummyFeature;
 
 // All the features declared for Android below that are also used in Java,
 // should also be declared in:
 // org.chromium.components.feature_engagement_tracker.FeatureConstants.
 #if defined(OS_ANDROID)
 extern const base::Feature kIPHDataSaverDetailFeature;
 extern const base::Feature kIPHDataSaverPreviewFeature;
 extern const base::Feature kIPHDownloadHomeFeature;
 extern const base::Feature kIPHDownloadPageFeature;
 extern const base::Feature kIPHDownloadPageScreenshotFeature;
+extern const base::Feature kIPHMediaDownloadFeature;
 #endif  // defined(OS_ANDROID)
 
 #if defined(OS_WIN) || defined(OS_LINUX)
 extern const base::Feature kIPHIncognitoWindowFeature;
 extern const base::Feature kIPHNewTabFeature;
 #endif  // defined(OS_WIN) || defined(OS_LINUX)
 
 }  // namespace feature_engagement_tracker
 
 #endif  // COMPONENTS_FEATURE_ENGAGEMENT_TRACKER_PUBLIC_FEATURE_CONSTANTS_H_