mash: Convert ShelfView to wm common types, clean up Shelf access

ash/common/shelf/wm_shelf.cc

Index: ash/common/shelf/wm_shelf.cc
diff --git a/ash/common/shelf/wm_shelf.cc b/ash/common/shelf/wm_shelf.cc
new file mode 100644
index 0000000000000000000000000000000000000000..646ebed36025f0bcefa8beb4ad2545123599b969
--- /dev/null
+++ b/ash/common/shelf/wm_shelf.cc
@@ -0,0 +1,44 @@
+// 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/shelf/wm_shelf.h"
+
+#include "base/logging.h"
+
+namespace ash {
+
+bool WmShelf::IsHorizontalAlignment() const {
+  switch (GetAlignment()) {
+    case SHELF_ALIGNMENT_BOTTOM:
+    case SHELF_ALIGNMENT_BOTTOM_LOCKED:
+      return true;
+    case SHELF_ALIGNMENT_LEFT:
+    case SHELF_ALIGNMENT_RIGHT:
+      return false;
+  }
+  NOTREACHED();
+  return true;
+}
+
+int WmShelf::SelectValueForShelfAlignment(int bottom,
+                                          int left,
+                                          int right) const {
+  switch (GetAlignment()) {
+    case SHELF_ALIGNMENT_BOTTOM:
+    case SHELF_ALIGNMENT_BOTTOM_LOCKED:
+      return bottom;
+    case SHELF_ALIGNMENT_LEFT:
+      return left;
+    case SHELF_ALIGNMENT_RIGHT:
+      return right;
+  }
+  NOTREACHED();
+  return bottom;
+}
+
+int WmShelf::PrimaryAxisValue(int horizontal, int vertical) const {
+  return IsHorizontalAlignment() ? horizontal : vertical;
+}
+
+}  // namespace ash