Removes most aura dependencies from DockedWindowResizer

ash/wm/aura/wm_window_aura.cc

Index: ash/wm/aura/wm_window_aura.cc
diff --git a/ash/wm/aura/wm_window_aura.cc b/ash/wm/aura/wm_window_aura.cc
index 9dcb68bcbdcf20ef0043659ea9c0e7c3843984da..2dde352e5e023b3165d81a8aa2ffe85e218fe335 100644
--- a/ash/wm/aura/wm_window_aura.cc
+++ b/ash/wm/aura/wm_window_aura.cc
@@ -15,6 +15,7 @@
 #include "ash/wm/window_state_aura.h"
 #include "ash/wm/window_util.h"
 #include "ui/aura/client/aura_constants.h"
+#include "ui/aura/client/window_tree_client.h"
 #include "ui/aura/layout_manager.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_delegate.h"
@@ -190,6 +191,12 @@ WmWindow* WmWindowAura::GetToplevelWindow() {
   return Get(window_->GetToplevelWindow());
 }
 
+void WmWindowAura::SetParentUsingContext(WmWindow* context,
+                                         const gfx::Rect& screen_bounds) {
+  aura::client::ParentWindowWithContext(window_, GetAuraWindow(context),
+                                        screen_bounds);
+}
+
 void WmWindowAura::AddChild(WmWindow* window) {
   window_->AddChild(GetAuraWindow(window));
 }