mash: Partially migrate WorkspaceController to ash common.

ash/common/wm/wm_window_animations.cc

Index: ash/common/wm/wm_window_animations.cc
diff --git a/ash/common/wm/wm_window_animations.cc b/ash/common/wm/wm_window_animations.cc
new file mode 100644
index 0000000000000000000000000000000000000000..1fe83b152720031e5ea0762045048e5b5fafb346
--- /dev/null
+++ b/ash/common/wm/wm_window_animations.cc
@@ -0,0 +1,29 @@
+// Copyright 2016 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.
+
+#include "ash/common/wm/wm_window_animations.h"
+
+#include "ui/compositor/layer.h"
+#include "ui/gfx/transform.h"
+
+namespace ash {
+
+// Returns scale related to the specified AshWindowScaleType.

[James Cook, 2016/08/11 23:27:35]

Doesn't seem to apply anymore.

[msw, 2016/08/12 00:17:15]

Done.

+void SetTransformForScaleAnimation(ui::Layer* layer,
+                                   LayerScaleAnimationDirection type) {
+  // Scales for AshWindow above/below current workspace.

[James Cook, 2016/08/11 23:27:35]

WmWindow? just window?

[msw, 2016/08/12 00:17:15]

Done.

+  const float kLayerScaleAboveSize = 1.1f;
+  const float kLayerScaleBelowSize = .9f;
+
+  const float scale = type == LAYER_SCALE_ANIMATION_ABOVE
+                          ? kLayerScaleAboveSize
+                          : kLayerScaleBelowSize;
+  gfx::Transform transform;
+  transform.Translate(-layer->bounds().width() * (scale - 1.0f) / 2,
+                      -layer->bounds().height() * (scale - 1.0f) / 2);
+  transform.Scale(scale, scale);
+  layer->SetTransform(transform);
+}
+
+}  // namespace ash