Converts mash to use Shell

ash/root_window_controller.h

Index: ash/root_window_controller.h
diff --git a/ash/root_window_controller.h b/ash/root_window_controller.h
index b247545d55673443cd07f09899d7f93617a8465e..163e601e9108df6f5459100076b53ec93f4dcef4 100644
--- a/ash/root_window_controller.h
+++ b/ash/root_window_controller.h
@@ -101,6 +101,11 @@ class ASH_EXPORT RootWindowController : public ShellObserver {
   // Returns the RootWindowController of the target root window.
   static RootWindowController* ForTargetRootWindow();
 
+  static std::vector<RootWindowController*> root_window_controllers() {
+    return root_window_controllers_ ? *root_window_controllers_
+                                    : std::vector<RootWindowController*>();

[James Cook, 2017/01/18 01:00:24]

nit: #include <vector>

[sky, 2017/01/18 04:00:07]

Done.

+  }
+
   // Configures |init_params| prior to initializing |widget|.
   // |shell_container_id| is the id of the container to parent |widget| to.
   // TODO(sky): remove this, http://crbug.com/671246.
@@ -371,6 +376,8 @@ class ASH_EXPORT RootWindowController : public ShellObserver {
 
   std::unique_ptr<::wm::ScopedCaptureClient> capture_client_;
 
+  static std::vector<RootWindowController*>* root_window_controllers_;
+
   DISALLOW_COPY_AND_ASSIGN(RootWindowController);
 };