Third part of porting Chrome Ash to Windows 7

ash/host/window_tree_host_factory_win.cc

Index: ash/host/window_tree_host_factory_win.cc
diff --git a/ash/host/window_tree_host_factory_win.cc b/ash/host/window_tree_host_factory_win.cc
index 42eb753876eb2fd8c2b71ab1b3f32142e5d4127f..1cd8670097ef636387f70b623d17d7c517869713 100644
--- a/ash/host/window_tree_host_factory_win.cc
+++ b/ash/host/window_tree_host_factory_win.cc
@@ -14,27 +14,32 @@ namespace {
 
 class WindowTreeHostFactoryImpl : public ash::WindowTreeHostFactory {
  public:
-  WindowTreeHostFactoryImpl() {}
+  explicit WindowTreeHostFactoryImpl(bool test_mode) : test_mode_(test_mode) {
+  }
 
-  // Overridden from WindowTreeHostFactory:
   virtual aura::WindowTreeHost* CreateWindowTreeHost(
       const gfx::Rect& initial_bounds) OVERRIDE {
-    if (base::win::GetVersion() >= base::win::VERSION_WIN8 &&
-        !CommandLine::ForCurrentProcess()->HasSwitch(
-            ash::switches::kForceAshToDesktop))
+    if (test_mode_)
+      return aura::WindowTreeHost::Create(initial_bounds);
+    else
       return aura::RemoteWindowTreeHostWin::Create(initial_bounds);
-
-    return aura::WindowTreeHost::Create(initial_bounds);
   }
+
+ private:
+   bool test_mode_;
 };
 
 }
 
 namespace ash {
+// static
+WindowTreeHostFactory* WindowTreeHostFactory::CreateForTest() {
+  return new WindowTreeHostFactoryImpl(true);
+}
 
 // static
 WindowTreeHostFactory* WindowTreeHostFactory::Create() {
-  return new WindowTreeHostFactoryImpl;
+  return new WindowTreeHostFactoryImpl(false);
 }
 
 }  // namespace ash