Ignore fullscreen windows which are behind other windows for fullscreen mode.

ash/wm/workspace_controller.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_controller.h"
 
 #include "ash/shelf/shelf_layout_manager.h"
 #include "ash/shell.h"
 #include "ash/shell_window_ids.h"
 #include "ash/wm/base_layout_manager.h"
@@ skipping 56 matching lines @@
     wm::WindowState* window_state = wm::GetWindowState(*i);
     if (window_state->ignored_by_shelf())
       continue;
     ui::Layer* layer = (*i)->layer();
     if (!layer->GetTargetVisibility() || layer->GetTargetOpacity() == 0.0f)
       continue;
     if (window_state->IsMaximized()) {
       // An untracked window may still be fullscreen so we keep iterating when
       // we hit a maximized window.
       has_maximized_window = true;
-    } else if (window_state->IsFullscreen()) {
+    } else if (*i == windows.back() && window_state->IsFullscreen()) {

[flackr, 2013/12/03 22:05:55]

Hang on, this check for topmost doesn't seem to be working in practice. I'll
ping you when I address this.

+      // Only enter the full screen state if the topmost window is fullscreen.
       return WORKSPACE_WINDOW_STATE_FULL_SCREEN;
     }
     if (!window_overlaps_launcher && (*i)->bounds().Intersects(shelf_bounds))
       window_overlaps_launcher = true;
   }
   if (has_maximized_window)
     return WORKSPACE_WINDOW_STATE_MAXIMIZED;
 
   return window_overlaps_launcher ?
       WORKSPACE_WINDOW_STATE_WINDOW_OVERLAPS_SHELF :
@@ skipping 31 matching lines @@
     settings.SetTweenType(gfx::Tween::EASE_OUT);
     settings.SetTransitionDuration(
         base::TimeDelta::FromMilliseconds(kCrossFadeDurationMS));
     viewport_->layer()->SetTransform(gfx::Transform());
     viewport_->layer()->SetOpacity(1.0f);
   }
 }
 
 }  // namespace internal
 }  // namespace ash