Make win_aura work without ash.

ui/aura/root_window_host_win.cc

Index: ui/aura/root_window_host_win.cc
===================================================================
--- ui/aura/root_window_host_win.cc	(revision 134107)
+++ ui/aura/root_window_host_win.cc	(working copy)
@@ -12,6 +12,7 @@
 #include "ui/aura/env.h"
 #include "ui/aura/event.h"
 #include "ui/aura/root_window.h"
+#include "ui/base/view_prop.h"
 
 using std::max;
 using std::min;
@@ -20,6 +21,8 @@
 
 namespace {
 
+const char* kRootWindowHostWinKey = "__AURA_ROOT_WINDOW_HOST_WIN__";
+
 const wchar_t* GetCursorId(gfx::NativeCursor native_cursor) {
   switch (native_cursor.native_type()) {
     case ui::kCursorNull:
@@ -108,6 +111,13 @@
 }
 
 // static
+RootWindowHost* RootWindowHost::GetForAcceleratedWidget(
+    gfx::AcceleratedWidget accelerated_widget) {
+  return reinterpret_cast<RootWindowHost*>(
+      ui::ViewProp::GetValue(accelerated_widget, kRootWindowHostWinKey));
+}
+
+// static
 gfx::Size RootWindowHost::GetNativeScreenSize() {
   return gfx::Size(GetSystemMetrics(SM_CXSCREEN),
                    GetSystemMetrics(SM_CYSCREEN));
@@ -121,6 +131,7 @@
       saved_window_ex_style_(0) {
   Init(NULL, bounds);
   SetWindowText(hwnd(), L"aura::RootWindow!");
+  prop_.reset(new ui::ViewProp(hwnd(), kRootWindowHostWinKey, this));
 }
 
 RootWindowHostWin::~RootWindowHostWin() {
@@ -131,6 +142,10 @@
   root_window_ = root_window;
 }
 
+RootWindow* RootWindowHostWin::GetRootWindow() {
+  return root_window_;
+}
+
 gfx::AcceleratedWidget RootWindowHostWin::GetAcceleratedWidget() {
   return hwnd();
 }