mash: Move shelf_navigator.* to //ash/common/shelf

ash/shelf/shelf_navigator.cc

-// Copyright 2013 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/shelf/shelf_navigator.h"
-
-#include "ash/common/shelf/shelf_model.h"
-
-namespace ash {
-
-namespace {
-
-// Returns true if accelerator processing should skip the shelf item with the
-// specified type.
-bool ShouldSkip(ShelfItemType type) {
-  return type == TYPE_APP_LIST || type == TYPE_BROWSER_SHORTCUT ||
-         type == TYPE_APP_SHORTCUT || type == TYPE_WINDOWED_APP;
-}
-
-}  // namespace
-
-int GetNextActivatedItemIndex(const ShelfModel& model,
-                              CycleDirection direction) {
-  const ShelfItems& items = model.items();
-  int item_count = model.item_count();
-  int current_index = -1;
-  int first_running = -1;
-
-  for (int i = 0; i < item_count; ++i) {
-    const ShelfItem& item = items[i];
-    if (ShouldSkip(item.type))
-      continue;
-
-    if (item.status == STATUS_RUNNING && first_running < 0)
-      first_running = i;
-
-    if (item.status == STATUS_ACTIVE) {
-      current_index = i;
-      break;
-    }
-  }
-
-  // If nothing is active, try to active the first running item.
-  if (current_index < 0) {
-    if (first_running >= 0)
-      return first_running;
-    else
-      return -1;
-  }
-
-  int step = (direction == CYCLE_FORWARD) ? 1 : -1;
-
-  // Find the next item and activate it.
-  for (int i = (current_index + step + item_count) % item_count;
-       i != current_index; i = (i + step + item_count) % item_count) {
-    const ShelfItem& item = items[i];
-    if (ShouldSkip(item.type))
-      continue;
-
-    // Skip already active item.
-    if (item.status == STATUS_ACTIVE)
-      continue;
-
-    return i;
-  }
-
-  return -1;
-}
-
-}  // namespace ash