Makes GetRootWindow() public on Window so we can begin to convert uses of RootWindow::GetInstance().

ui/aura/root_window.cc

Index: ui/aura/root_window.cc
===================================================================
--- ui/aura/root_window.cc	(revision 119894)
+++ ui/aura/root_window.cc	(working copy)
@@ -407,6 +407,16 @@
   gesture_recognizer_.reset(gr);
 }
 
+#if !defined(NDEBUG)
+void RootWindow::ToggleFullScreen() {
+  host_->ToggleFullScreen();
+}
+#endif
+
+RootWindow* RootWindow::GetRootWindow() {
+  return this;
+}
+
 void RootWindow::SetTransform(const ui::Transform& transform) {
   Window::SetTransform(transform);
 
@@ -416,12 +426,6 @@
     OnHostResized(host_->GetSize());
 }
 
-#if !defined(NDEBUG)
-void RootWindow::ToggleFullScreen() {
-  host_->ToggleFullScreen();
-}
-#endif
-
 ////////////////////////////////////////////////////////////////////////////////
 // RootWindow, private:
 
@@ -627,10 +631,6 @@
   return this;
 }
 
-RootWindow* RootWindow::GetRootWindow() {
-  return this;
-}
-
 void RootWindow::OnWindowDetachingFromRootWindow(Window* detached) {
   DCHECK(capture_window_ != this);