Eliminate Shell::RootWindowList in favor of aura::Window::Windows.

ash/wm/workspace/workspace_window_resizer.cc

Index: ash/wm/workspace/workspace_window_resizer.cc
diff --git a/ash/wm/workspace/workspace_window_resizer.cc b/ash/wm/workspace/workspace_window_resizer.cc
index 731fcb37a92ac3e24bc558ee1c89428d34e25b00..ce56c55c39a5a26bcd0c44dbad5d5456dd7ec1f3 100644
--- a/ash/wm/workspace/workspace_window_resizer.cc
+++ b/ash/wm/workspace/workspace_window_resizer.cc
@@ -741,10 +741,10 @@ bool WorkspaceWindowResizer::UpdateMagnetismWindow(const gfx::Rect& bounds,
   if (!window_state()->CanResize() || !window_state()->tracked_by_workspace())
     return false;
 
-  Shell::RootWindowList root_windows = Shell::GetAllRootWindows();
-  for (Shell::RootWindowList::iterator iter = root_windows.begin();
+  aura::Window::Windows root_windows = Shell::GetAllRootWindows();
+  for (aura::Window::Windows::iterator iter = root_windows.begin();
        iter != root_windows.end(); ++iter) {
-    const aura::RootWindow* root_window = *iter;
+    const aura::Window* root_window = *iter;
     // Test all children from the desktop in each root window.
     const aura::Window::Windows& children = Shell::GetContainer(
         root_window, kShellWindowId_DefaultContainer)->children();