Split Screen mode implementation

athena/wm/window_overview_mode.cc

Index: athena/wm/window_overview_mode.cc
diff --git a/athena/wm/window_overview_mode.cc b/athena/wm/window_overview_mode.cc
index b37339e3cf7cca7b76aad83cc3e4ae66a5508c24..076a335b00e8bade06a0eaf879fded93dcdfe5c5 100644
--- a/athena/wm/window_overview_mode.cc
+++ b/athena/wm/window_overview_mode.cc
@@ -92,8 +92,10 @@ class WindowOverviewModeImpl : public WindowOverviewMode,
                                public ui::EventHandler {
  public:
   WindowOverviewModeImpl(aura::Window* container,
+                         aura::Window::Windows windows,
                          WindowOverviewModeDelegate* delegate)
       : container_(container),
+        windows_(windows),
         delegate_(delegate),
         scoped_targeter_(new aura::ScopedWindowTargeter(
             container,
@@ -110,10 +112,9 @@ class WindowOverviewModeImpl : public WindowOverviewMode,
   virtual ~WindowOverviewModeImpl() {
     container_->set_target_handler(container_->delegate());
 
-    aura::Window::Windows windows = container_->children();
-    if (windows.empty())
+    if (windows_.empty())
       return;
-    std::for_each(windows.begin(), windows.end(), &RestoreWindowState);
+    std::for_each(windows_.begin(), windows_.end(), &RestoreWindowState);
   }
 
  private:
@@ -121,8 +122,7 @@ class WindowOverviewModeImpl : public WindowOverviewMode,
   // positions. The transforms are set in the |kWindowOverviewState| property of
   // the windows.
   void ComputeTerminalStatesForAllWindows() {
-    aura::Window::Windows windows = container_->children();
-    size_t window_count = windows.size();
+    size_t window_count = windows_.size();
     size_t index = 0;
     const gfx::Size container_size = container_->bounds().size();
 
@@ -131,8 +131,8 @@ class WindowOverviewModeImpl : public WindowOverviewMode,
     const float kMinScale = 0.6f;
     const float kMaxScale = 0.95f;
 
-    for (aura::Window::Windows::reverse_iterator iter = windows.rbegin();
-         iter != windows.rend();
+    for (aura::Window::Windows::reverse_iterator iter = windows_.rbegin();
+         iter != windows_.rend();
          ++iter, ++index) {
       aura::Window* window = (*iter);
 
@@ -159,13 +159,12 @@ class WindowOverviewModeImpl : public WindowOverviewMode,
 
   // Sets the initial position for the windows for the overview mode.
   void SetInitialWindowStates() {
-    aura::Window::Windows windows = container_->children();
-    size_t window_count = windows.size();
+    size_t window_count = windows_.size();
     // The initial overview state of the topmost three windows.
     const float kInitialProgress[] = { 0.5f, 0.05f, 0.01f };
     for (size_t i = 0; i < window_count; ++i) {
       float progress = 0.f;
-      aura::Window* window = windows[window_count - 1 - i];
+      aura::Window* window = windows_[window_count - 1 - i];
       if (i < arraysize(kInitialProgress))
         progress = kInitialProgress[i];
 
@@ -194,7 +193,7 @@ class WindowOverviewModeImpl : public WindowOverviewMode,
   scoped_ptr<wm::Shadow> CreateShadowForWindow(aura::Window* window) {
     scoped_ptr<wm::Shadow> shadow(new wm::Shadow());
     shadow->Init(wm::Shadow::STYLE_ACTIVE);
-    shadow->SetContentBounds(gfx::Rect(window->bounds().size()));
+    shadow->SetContentBounds(gfx::Rect(container_->bounds().size()));
     shadow->layer()->SetVisible(true);
     window->layer()->Add(shadow->layer());
     return shadow.Pass();
@@ -222,13 +221,12 @@ class WindowOverviewModeImpl : public WindowOverviewMode,
   // scrolling up; and positive when scrolling down.
   void DoScroll(float delta_y) {
     const float kEpsilon = 1e-3f;
-    aura::Window::Windows windows = container_->children();
     float delta_y_p = std::abs(delta_y) / GetScrollableHeight();
     if (delta_y < 0) {
       // Scroll up. Start with the top-most (i.e. behind-most in terms of
       // z-index) window, and try to scroll them up.
-      for (aura::Window::Windows::iterator iter = windows.begin();
-           delta_y_p > kEpsilon && iter != windows.end();
+      for (aura::Window::Windows::iterator iter = windows_.begin();
+           delta_y_p > kEpsilon && iter != windows_.end();
            ++iter) {
         aura::Window* window = (*iter);
         WindowOverviewState* state = window->GetProperty(kWindowOverviewState);
@@ -243,8 +241,8 @@ class WindowOverviewModeImpl : public WindowOverviewMode,
     } else {
       // Scroll down. Start with the bottom-most (i.e. front-most in terms of
       // z-index) window, and try to scroll them down.
-      for (aura::Window::Windows::reverse_iterator iter = windows.rbegin();
-           delta_y_p > kEpsilon && iter != windows.rend();
+      for (aura::Window::Windows::reverse_iterator iter = windows_.rbegin();
+           delta_y_p > kEpsilon && iter != windows_.rend();
            ++iter) {
         aura::Window* window = (*iter);
         WindowOverviewState* state = window->GetProperty(kWindowOverviewState);
@@ -294,6 +292,9 @@ class WindowOverviewModeImpl : public WindowOverviewMode,
   }
 
   aura::Window* container_;
+  // The stack of windows to show in the overview mode
+  // TODO (mfomitchev): Should this be const?
+  /*const*/ aura::Window::Windows windows_;
   WindowOverviewModeDelegate* delegate_;
   scoped_ptr<aura::ScopedWindowTargeter> scoped_targeter_;
 
@@ -305,9 +306,10 @@ class WindowOverviewModeImpl : public WindowOverviewMode,
 // static
 scoped_ptr<WindowOverviewMode> WindowOverviewMode::Create(
     aura::Window* container,
+    aura::Window::Windows windows,
     WindowOverviewModeDelegate* delegate) {
   return scoped_ptr<WindowOverviewMode>(
-      new WindowOverviewModeImpl(container, delegate));
+      new WindowOverviewModeImpl(container, windows, delegate));
 }
 
 }  // namespace athena