cros: Suspend media sessions with display off trigger by tablet power button

chrome/browser/chromeos/chrome_browser_main_chromeos.cc

Index: chrome/browser/chromeos/chrome_browser_main_chromeos.cc
diff --git a/chrome/browser/chromeos/chrome_browser_main_chromeos.cc b/chrome/browser/chromeos/chrome_browser_main_chromeos.cc
index 998ce5db10de0e4555ba72d2c9fe3e031663b749..eaf9186214469cd9926ac4b4e7b1bab75cf89334 100644
--- a/chrome/browser/chromeos/chrome_browser_main_chromeos.cc
+++ b/chrome/browser/chromeos/chrome_browser_main_chromeos.cc
@@ -153,6 +153,7 @@
 #include "device/bluetooth/bluetooth_adapter_factory.h"
 #include "device/bluetooth/dbus/bluez_dbus_manager.h"
 #include "media/audio/sounds/sounds_manager.h"
+#include "media/base/media_switches.h"
 #include "net/base/network_change_notifier.h"
 #include "net/cert/nss_cert_database.h"
 #include "net/cert/nss_cert_database_chromeos.h"
@@ -914,6 +915,9 @@ void ChromeBrowserMainPartsChromeos::PreBrowserStart() {
     system::InputDeviceSettings::Get()->SetTapToClick(true);
   }
 
+  base::CommandLine::ForCurrentProcess()->AppendSwitch(
+      ::switches::kEnableInternalMediaSession);

[Daniel Erat, 2017/05/17 01:22:25]

it seems strange to do this programmatically here. we usually pass switches from
session_manager, or perhaps better, just turn the feature on automatically
within chrome when OS_CHROMEOS is defined.

[Qiang(Joe) Xu, 2017/05/22 22:58:47]

I moved it to ChromeShellDelegate::PreInit(), is that in line with "turn the
feature on automatically within chrome when OS_CHROMEOS is defined"?

+
   ChromeBrowserMainPartsLinux::PreBrowserStart();
 }