Move the concept of Activation to the Shell.

ui/aura_shell/workspace/workspace.cc

 // Copyright (c) 2011 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 "ui/aura_shell/workspace/workspace.h"
 
 #include <algorithm>
 
 #include "base/logging.h"
 #include "ui/aura/client/aura_constants.h"
 #include "ui/aura/root_window.h"
 #include "ui/aura/window.h"
 #include "ui/aura_shell/property_util.h"
+#include "ui/aura_shell/window_util.h"
 #include "ui/aura_shell/workspace/workspace_manager.h"
 #include "ui/base/ui_base_types.h"
 #include "ui/gfx/compositor/layer.h"
 #include "ui/gfx/compositor/layer_animator.h"
 
 namespace {
 // Horizontal margin between windows.
 const int kWindowHorizontalMargin = 10;
 
 // Maximum number of windows a workspace can have.
@@ skipping 64 matching lines @@
   windows_.erase(std::find(windows_.begin(), windows_.end(), window));
   Layout(NULL);
 }
 
 bool Workspace::Contains(aura::Window* window) const {
   return std::find(windows_.begin(), windows_.end(), window) != windows_.end();
 }
 
 aura::Window* Workspace::FindRotateWindowForLocation(
     const gfx::Point& position) {
-  aura::Window* active = aura::RootWindow::GetInstance()->active_window();
+  aura::Window* active = aura_shell::GetActiveWindow();
   if (GetTotalWindowsWidth() < bounds_.width()) {
     // If all windows fit to the width of the workspace, it returns the
     // window which contains |position|'s x coordinate.
     for (aura::Window::Windows::const_iterator i = windows_.begin();
          i != windows_.end();
          ++i) {
       if (active == *i)
         continue;
       gfx::Rect bounds = (*i)->GetTargetBounds();
       if (bounds.x() < position.x() && position.x() < bounds.right())
@@ skipping 166 matching lines @@
 
 // static
 size_t Workspace::SetMaxWindowsCount(size_t max) {
   int old = g_max_windows_per_workspace;
   g_max_windows_per_workspace = max;
   return old;
 }
 
 }  // namespace internal
 }  // namespace aura_shell