Ash: Add resize border shadow effect

* Add ResizeShadow that uses solid-color layers to draw the resize border shadow effect.
* Add ResizeShadowController to create ResizeShadows and track bounds changes for windows.
* Wire both into ToplevelWindowEventFilter to track mouse move/enter events near (but not inside) the window frame.

BUG=118325
TEST=visual, hover mouse near window edges, drag windows

Review URL: https://chromiumcodereview.appspot.com/9677070

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@127268 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 61 insertions, 0 deletions

diff --git a/ash/wm/resize_shadow_controller.h b/ash/wm/resize_shadow_controller.h
new file mode 100644
index 0000000..08294d0
--- /dev/null
+++ b/ash/wm/resize_shadow_controller.h
@@ -0,0 +1,61 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef ASH_WM_RESIZE_SHADOW_CONTROLLER_H_
+#define ASH_WM_RESIZE_SHADOW_CONTROLLER_H_
+#pragma once
+
+#include <map>
+
+#include "base/basictypes.h"
+#include "base/compiler_specific.h"
+#include "base/memory/linked_ptr.h"
+#include "ui/aura/window_observer.h"
+
+namespace aura {
+class Window;
+}
+
+namespace ash {
+namespace internal {
+
+class ResizeShadow;
+
+// ResizeShadowController observes changes to resizable windows and shows
+// a resize handle visual effect when the cursor is near the edges.
+class ResizeShadowController : public aura::WindowObserver {
+ public:
+  ResizeShadowController();
+  virtual ~ResizeShadowController();
+
+  // Shows the appropriate shadow for a given |window| and |hit_test| location.
+  void ShowShadow(aura::Window* window, int hit_test);
+
+  // Hides the shadow for a |window|, if it has one.
+  void HideShadow(aura::Window* window);
+
+  // aura::WindowObserver overrides:
+  virtual void OnWindowBoundsChanged(
+      aura::Window* window, const gfx::Rect& bounds) OVERRIDE;
+  virtual void OnWindowDestroyed(aura::Window* window) OVERRIDE;
+
+ private:
+  typedef std::map<aura::Window*, linked_ptr<ResizeShadow> > WindowShadowMap;
+
+  // Creates a shadow for a given window and returns it.  |window_shadows_|
+  // owns the memory.
+  ResizeShadow* CreateShadow(aura::Window* window);
+
+  // Returns the resize shadow for |window| or NULL if no shadow exists.
+  ResizeShadow* GetShadowForWindow(aura::Window* window);
+
+  WindowShadowMap window_shadows_;
+
+  DISALLOW_COPY_AND_ASSIGN(ResizeShadowController);
+};
+
+}  // namespace internal
+}  // namespace ash
+
+#endif  // ASH_WM_RESIZE_SHADOW_CONTROLLER_H_