[ash-md] Adds support for gesture to move selection in overview mode

ash/common/wm/overview/window_grid.cc

 // Copyright 2014 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/overview/window_grid.h"
 
 #include <algorithm>
 #include <functional>
 #include <set>
 #include <utility>
@@ skipping 264 matching lines @@
 
 WindowGrid::WindowGrid(WmWindow* root_window,
                        const std::vector<WmWindow*>& windows,
                        WindowSelector* window_selector)
     : root_window_(root_window),
       window_selector_(window_selector),
       window_observer_(this),
       window_state_observer_(this),
       selected_index_(0),
       num_columns_(0),
-      prepared_for_overview_(false) {
+      prepared_for_overview_(false),
+      skip_first_(false) {
   std::vector<WmWindow*> windows_in_root;
   for (auto* window : windows) {
     if (window->GetRootWindow() == root_window)
       windows_in_root.push_back(window);
   }
 
   for (auto* window : windows_in_root) {
     window_observer_.Add(window);
     window_state_observer_.Add(window->GetWindowState());
     window_list_.push_back(
@@ skipping 185 matching lines @@
   // [up] key is equivalent to [left] key and [down] key is equivalent to
   // [right] key.
   if (!selection_widget_) {
     switch (direction) {
       case WindowSelector::UP:
       case WindowSelector::LEFT:
         selected_index_ = window_list_.size() - 1;
         break;
       case WindowSelector::DOWN:
       case WindowSelector::RIGHT:
-        selected_index_ = 0;
+        selected_index_ = (skip_first_ && window_list_.size() > 1) ? 1 : 0;
         break;
     }
+    skip_first_ = false;
     changed_selection_index = true;
   }
   while (!changed_selection_index ||
          (!out_of_bounds && window_list_[selected_index_]->dimmed())) {
     switch (direction) {
       case WindowSelector::UP:
       case WindowSelector::LEFT:
         if (selected_index_ == 0)
           out_of_bounds = true;
         selected_index_--;
@@ skipping 334 matching lines @@
         *min_right = left;
       if (*max_right < left)
         *max_right = left;
     }
     *max_bottom = top + height;
   }
   return windows_fit;
 }
 
 }  // namespace ash