ash: Add accelerator for snapping windows left/right.

ash/wm/workspace/snap_sizer.cc

 // 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.
 
 #include "ash/wm/workspace/snap_sizer.h"
 
 #include <cmath>
 
 #include "ash/screen_ash.h"
 #include "ash/wm/window_resizer.h"
@@ skipping 48 matching lines @@
     if (std::abs(location.x() - last_adjust_x_) >= kPixelsBeforeAdjust ||
         (along_edge && num_moves_since_adjust_ >= kMovesBeforeAdjust)) {
       ChangeBounds(location.x(),
                    CalculateIncrement(location.x(), last_adjust_x_));
     }
   }
   last_update_x_ = location.x();
   time_last_update_ = base::TimeTicks::Now();
 }
 
+gfx::Rect SnapSizer::GetSnapBounds(const gfx::Rect& bounds) {
+  size_t current;
+  for (current = 0; current < arraysize(kPercents); ++current) {
+    gfx::Rect target = GetTargetBoundsForPercent(current);
+    if (target == bounds) {
+      ++current;
+      break;
+    }
+  }
+  return GetTargetBoundsForPercent(current % arraysize(kPercents));
+}
+
 int SnapSizer::CalculateIncrement(int x, int reference_x) const {
   if (AlongEdge(x))
     return 1;
   if (x == reference_x)
     return 0;
   if (edge_ == LEFT_EDGE) {
     if (x < reference_x)
       return 1;
     return -1;
   }
   // edge_ == RIGHT_EDGE.
   if (x > reference_x)
     return 1;
   return -1;
 }
 
 void SnapSizer::ChangeBounds(int x, int delta) {
   int index = std::min(static_cast<int>(arraysize(kPercents)) - 1,
                        std::max(percent_index_ + delta, 0));
   if (index != percent_index_) {
     percent_index_ = index;
     target_bounds_ = GetTargetBounds();
   }
   num_moves_since_adjust_ = 0;
   last_adjust_x_ = x;
 }
 
 gfx::Rect SnapSizer::GetTargetBounds() const {
+  return GetTargetBoundsForPercent(percent_index_);
+}
+
+gfx::Rect SnapSizer::GetTargetBoundsForPercent(int percent_index) const {
   gfx::Rect work_area(ScreenAsh::GetUnmaximizedWorkAreaBounds(window_));
   int y = WindowResizer::AlignToGridRoundUp(work_area.y(), grid_size_);
   // We don't align to the bottom of the grid as the launcher may not
   // necessarily align to the grid (happens when auto-hidden).
   int max_y = work_area.bottom();
-  int width = static_cast<float>(work_area.width()) * kPercents[percent_index_];
+  int width = static_cast<float>(work_area.width()) * kPercents[percent_index];
   if (edge_ == LEFT_EDGE) {
     int x = WindowResizer::AlignToGridRoundUp(work_area.x(), grid_size_);
     int mid_x = WindowResizer::AlignToGridRoundUp(
         work_area.x() + width, grid_size_);
     return gfx::Rect(x, y, mid_x - x, max_y - y);
   }
   int max_x =
       WindowResizer::AlignToGridRoundDown(work_area.right(), grid_size_);
   int x = WindowResizer::AlignToGridRoundUp(max_x - width, grid_size_);
   return gfx::Rect(x , y, max_x - x, max_y - y);
 }
 
 bool SnapSizer::AlongEdge(int x) const {
   // TODO: need to support multi-monitor.
   gfx::Rect area(gfx::Screen::GetMonitorNearestWindow(window_).bounds());
   return (x <= area.x()) || (x >= area.right() - 1);
 }
 
 }  // namespace internal
 }  // namespace ash