Revert of Making WTH::InitCompositor() protected instead of public.

ui/aura/window_tree_host.cc

Index: ui/aura/window_tree_host.cc
diff --git a/ui/aura/window_tree_host.cc b/ui/aura/window_tree_host.cc
index c0baf2d340be172b9f9c303620a0b5d23dc4a30d..a1bac9be53163090c41ee54d31644ad12ae785ce 100644
--- a/ui/aura/window_tree_host.cc
+++ b/ui/aura/window_tree_host.cc
@@ -66,6 +66,14 @@
   window()->Show();
 }
 
+void WindowTreeHost::InitCompositor() {
+  compositor_->SetScaleAndSize(GetDeviceScaleFactorFromDisplay(window()),
+                               GetBoundsInPixels().size());
+  compositor_->SetRootLayer(window()->layer());
+  compositor_->SetDisplayColorSpace(
+      GetICCProfileForCurrentDisplay().GetColorSpace());
+}
+
 void WindowTreeHost::AddObserver(WindowTreeHostObserver* observer) {
   observers_.AddObserver(observer);
 }
@@ -261,14 +269,6 @@
   }
 }
 
-void WindowTreeHost::InitCompositor() {
-  compositor_->SetScaleAndSize(GetDeviceScaleFactorFromDisplay(window()),
-                               GetBoundsInPixels().size());
-  compositor_->SetRootLayer(window()->layer());
-  compositor_->SetDisplayColorSpace(
-      GetICCProfileForCurrentDisplay().GetColorSpace());
-}
-
 void WindowTreeHost::OnAcceleratedWidgetAvailable() {
   compositor_->SetAcceleratedWidget(GetAcceleratedWidget());
   prop_.reset(new ui::ViewProp(GetAcceleratedWidget(),