Relocate and refactor overview mode files.

ash/wm/overview/window_selector_delegate.h

Index: ash/wm/overview/window_selector_delegate.h
diff --git a/ash/wm/window_selector_delegate.h b/ash/wm/overview/window_selector_delegate.h
similarity index 80%
rename from ash/wm/window_selector_delegate.h
rename to ash/wm/overview/window_selector_delegate.h
index fd7677f1e779e6353bf83e7d352001fb165a6dde..2bce3ca3fd7e75caaedd340e18f24ae3a5ccbe2f 100644
--- a/ash/wm/window_selector_delegate.h
+++ b/ash/wm/overview/window_selector_delegate.h
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef ASH_WM_WINDOW_SELECTOR_DELEGATE_H_
-#define ASH_WM_WINDOW_SELECTOR_DELEGATE_H_
+#ifndef ASH_WM_OVERVIEW_WINDOW_SELECTOR_DELEGATE_H_
+#define ASH_WM_OVERVIEW_WINDOW_SELECTOR_DELEGATE_H_
 
 #include "ash/ash_export.h"
 #include "base/compiler_specific.h"
@@ -29,4 +29,4 @@ class ASH_EXPORT WindowSelectorDelegate {
 
 }  // namespace ash
 
-#endif  // ASH_WM_WINDOW_SELECTOR_DELEGATE_H_
+#endif  // ASH_WM_OVERVIEW_WINDOW_SELECTOR_DELEGATE_H_