mash: switch to the new pref service

chrome/common/chrome_features.cc

Index: chrome/common/chrome_features.cc
diff --git a/chrome/common/chrome_features.cc b/chrome/common/chrome_features.cc
index cb09f4cc2443f012208b0c327f55b88bf2849701..6c8e1cd67cb104dd7271b243b006690ad1a81c26 100644
--- a/chrome/common/chrome_features.cc
+++ b/chrome/common/chrome_features.cc
@@ -4,6 +4,8 @@
 
 #include "chrome/common/chrome_features.h"
 
+#include "base/command_line.h"
+#include "chrome/common/chrome_switches.h"
 #include "extensions/features/features.h"
 #include "ppapi/features/features.h"
 
@@ -306,4 +308,14 @@ const base::Feature kCrosCompUpdates{"CrosCompUpdates",
                                      base::FEATURE_ENABLED_BY_DEFAULT};
 #endif  // defined(OS_CHROMEOS)
 
+bool PrefServiceEnabled() {

[Sam McNally, 2017/03/27 05:42:10]

DON'T ADD RANDOM STUFF HERE.

[tibell, 2017/03/28 00:34:31]

ditto

+  return base::FeatureList::IsEnabled(features::kPrefService) ||
+#if BUILDFLAG(ENABLE_PACKAGE_MASH_SERVICES)
+         base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
+             switches::kMusConfig) == switches::kMash;

[jonross, 2017/03/27 14:26:38]

I'm a bit concerned about restricting this feature to mash only.

We have been using the IsRunningInMash() pattern a lot as a stopgap. To allow us
to turn off features which we haven't had the chance to implement mojoms for.
This has allowed us to test the system faster.

Once features have been ready we've had them utilize mojo apis both in mash, as
well as in classic ash settings.

There is some upcoming wallpaper and display settings changes with plans to use
the pref service in both modes.

[tibell, 2017/03/28 00:34:31]

See my reply in shell.cc

[jonross, 2017/03/28 13:57:26]

Acknowledged.

+#else
+         false;
+#endif
+}
+
 }  // namespace features