Allow autoplay unmuted for WebAPK in the manifest scope

content/renderer/render_view_impl.cc

 // Copyright (c) 2012 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/renderer/render_view_impl.h"
 
 #include <algorithm>
 #include <cmath>
 #include <memory>
 
@@ skipping 577 matching lines @@
       WebView::create(this, is_hidden() ? blink::WebPageVisibilityStateHidden
                                         : blink::WebPageVisibilityStateVisible);
   RenderWidget::Init(show_callback, webview_->widget());
 
   g_view_map.Get().insert(std::make_pair(webview(), this));
   g_routing_id_view_map.Get().insert(std::make_pair(GetRoutingID(), this));
 
   const base::CommandLine& command_line =
       *base::CommandLine::ForCurrentProcess();
 
+#if defined(OS_ANDROID)
+  webview()->settings()->setMediaPlaybackGestureWhitelistScope(
+      blink::WebString::fromASCII(command_line.GetSwitchValueASCII(
+          switches::kMediaPlaybackGestureWhitelistScope)));
+#endif

[mlamouri (slow - plz ping), 2017/02/10 14:28:45]

Instead of having `#if defined`, could we do:
```
if (command_line.HasSwitch(switches::kMediaPlayerGestureWhitelistScope)) {
  webview()->settings()->setMediaPlaybackGestureWhitelistScope(
      blink::WebString::fromASCII(command_line.GetSwitchValueASCII(
          switches::kMediaPlaybackGestureWhitelistScope)));
}
```

It will keep the feature multi-platform for those that might be interested to
use it.

[Zhiqiang Zhang (Slow), 2017/02/10 14:47:10]

Done.

+
   if (command_line.HasSwitch(switches::kStatsCollectionController))
     stats_collection_observer_.reset(new StatsCollectionObserver(this));
 
   // Debug cases of https://crbug.com/575245.
   base::debug::SetCrashKeyValue("rvinit_view_id",
                                 base::IntToString(GetRoutingID()));
   base::debug::SetCrashKeyValue("rvinit_proxy_id",
                                 base::IntToString(params.proxy_routing_id));
   base::debug::SetCrashKeyValue(
       "rvinit_main_frame_id", base::IntToString(params.main_frame_routing_id));
@@ skipping 2077 matching lines @@
                             INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
   }
 
   std::unique_ptr<InputEventAck> ack(
       new InputEventAck(InputEventAckSource::MAIN_THREAD, input_event->type(),
                         INPUT_EVENT_ACK_STATE_NOT_CONSUMED));
   OnInputEventAck(std::move(ack));
 }
 
 }  // namespace content