Fixes moving fully occluded windows when the a11y keyboard shows.

ash/wm/workspace/workspace_layout_manager.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/workspace_layout_manager.h"
 
 #include <algorithm>
 
 #include "ash/display/display_controller.h"
 #include "ash/root_window_controller.h"
@@ skipping 135 matching lines @@
   wm::WindowState* window_state = wm::GetWindowState(window);
   if (!new_bounds.IsEmpty()) {
     // Store existing bounds to be restored before resizing for keyboard if it
     // is not already stored.
     if (!window_state->HasRestoreBounds())
       window_state->SaveCurrentBoundsForRestore();
 
     gfx::Rect window_bounds = ScreenUtil::ConvertRectToScreen(
         window_,
         window->GetTargetBounds());
-    gfx::Rect intersect = gfx::IntersectRects(window_bounds, new_bounds);
-    int shift = std::min(intersect.height(),
-                         window->bounds().y() - work_area_in_parent_.y());
+    int vertical_displacement =
+        std::max(0, window_bounds.bottom() - new_bounds.y());
+    int shift = std::min(vertical_displacement,
+                         window_bounds.y() - work_area_in_parent_.y());
     if (shift > 0) {
-      gfx::Point origin(window->bounds().x(), window->bounds().y() - shift);
-      SetChildBounds(window, gfx::Rect(origin, window->bounds().size()));
+      gfx::Point origin(window_bounds.x(), window_bounds.y() - shift);
+      SetChildBounds(window, gfx::Rect(origin, window_bounds.size()));
     }
   } else if (window_state->HasRestoreBounds()) {
     // Keyboard hidden, restore original bounds if they exist.
     window_state->SetAndClearRestoreBounds();
   }
 }
 
 //////////////////////////////////////////////////////////////////////////////
 // WorkspaceLayoutManager, ash::ShellObserver implementation:
 
@@ skipping 146 matching lines @@
   bool is_fullscreen = GetRootWindowController(
       window_->GetRootWindow())->GetWindowForFullscreenMode() != NULL;
   if (is_fullscreen != is_fullscreen_) {
     ash::Shell::GetInstance()->NotifyFullscreenStateChange(
         is_fullscreen, window_->GetRootWindow());
     is_fullscreen_ = is_fullscreen;
   }
 }
 
 }  // namespace ash