[Media] Plumb a feature parameter for the background video keyframe distance.

content/public/common/web_preferences.cc

 // Copyright 2014 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/public/common/web_preferences.h"
 
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "build/build_config.h"
 #include "third_party/WebKit/public/web/WebSettings.h"
@@ skipping 205 matching lines @@
       default_maximum_page_scale_factor(5.f),
 #elif defined(OS_MACOSX)
       default_minimum_page_scale_factor(1.f),
       default_maximum_page_scale_factor(3.f),
 #else
       default_minimum_page_scale_factor(1.f),
       default_maximum_page_scale_factor(4.f),
 #endif
       hide_download_ui(false),
       background_video_track_optimization_enabled(false),
+      max_keyframe_distance_to_disable_background_video_sec(10),
       presentation_receiver(false) {
   standard_font_family_map[kCommonScript] =
       base::ASCIIToUTF16("Times New Roman");
   fixed_font_family_map[kCommonScript] = base::ASCIIToUTF16("Courier New");
   serif_font_family_map[kCommonScript] = base::ASCIIToUTF16("Times New Roman");
   sans_serif_font_family_map[kCommonScript] = base::ASCIIToUTF16("Arial");
   cursive_font_family_map[kCommonScript] = base::ASCIIToUTF16("Script");
   fantasy_font_family_map[kCommonScript] = base::ASCIIToUTF16("Impact");
   pictograph_font_family_map[kCommonScript] =
       base::ASCIIToUTF16("Times New Roman");
 }
 
 WebPreferences::WebPreferences(const WebPreferences& other) = default;
 
 WebPreferences::~WebPreferences() {
 }
 
 }  // namespace content