Add a NOT_DRAWN window in between the root_window and its children.

ash/common/wm/root_window_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/common/wm/root_window_layout_manager.h"
 
 #include "ash/common/wm_window.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_tracker.h"
 
 namespace ash {
-namespace wm {
 
-////////////////////////////////////////////////////////////////////////////////
-// RootWindowLayoutManager, public:
+namespace {
 
-RootWindowLayoutManager::RootWindowLayoutManager(WmWindow* owner)
-    : owner_(owner) {}
-
-RootWindowLayoutManager::~RootWindowLayoutManager() {}
-
-////////////////////////////////////////////////////////////////////////////////
-// RootWindowLayoutManager, aura::LayoutManager implementation:
-
-void RootWindowLayoutManager::OnWindowResized() {
-  const gfx::Rect fullscreen_bounds = gfx::Rect(owner_->GetBounds().size());
+void ResizeWindow(const aura::Window::Windows& children,
+                  const gfx::Rect& fullscreen_bounds,
+                  int depth) {
+  // Stop to prevent resizing non top level window such as tooltip.
+  if (depth > 3)
+    return;

[oshima, 2017/04/06 16:34:15]

I think this is ok in this CL, but we should make it more explicit, probably
using a property. Let's discuss offline.

[wutao, 2017/04/08 02:07:10]

Acknowledged.

 
   // Resize both our immediate children (the containers-of-containers animated
   // by PowerButtonController) and their children (the actual containers).
-  aura::WindowTracker children_tracker(owner_->aura_window()->children());
+  aura::WindowTracker children_tracker(children);
   while (!children_tracker.windows().empty()) {
     aura::Window* child = children_tracker.Pop();
     // Skip descendants of top-level windows, i.e. only resize containers and
     // other windows without a delegate, such as ScreenDimmer windows.
     if (child->GetToplevelWindow())
       continue;
 
     child->SetBounds(fullscreen_bounds);
-    aura::WindowTracker grandchildren_tracker(child->children());
-    while (!grandchildren_tracker.windows().empty()) {
-      child = grandchildren_tracker.Pop();
-      if (!child->GetToplevelWindow())
-        child->SetBounds(fullscreen_bounds);
-    }
+    ResizeWindow(child->children(), fullscreen_bounds, depth + 1);

[oshima, 2017/04/06 16:34:15]

can you define child_depth instead of adding every time?
const int child_depth = depth + 1;

[wutao, 2017/04/08 02:07:10]

Done.

   }
 }
 
+}  // namespace
+
+namespace wm {
+
+////////////////////////////////////////////////////////////////////////////////
+// RootWindowLayoutManager, public:
+
+RootWindowLayoutManager::RootWindowLayoutManager(WmWindow* owner)
+    : owner_(owner) {}
+
+RootWindowLayoutManager::~RootWindowLayoutManager() {}
+
+////////////////////////////////////////////////////////////////////////////////
+// RootWindowLayoutManager, aura::LayoutManager implementation:
+
+void RootWindowLayoutManager::OnWindowResized() {
+  ResizeWindow(owner_->aura_window()->children(),
+               gfx::Rect(owner_->GetBounds().size()), 1);

[oshima, 2017/04/06 16:34:15]

optional: it's probably easier for us to start with 0?

[wutao, 2017/04/08 02:07:10]

Done.

+}
+
 void RootWindowLayoutManager::OnWindowAddedToLayout(WmWindow* child) {}
 
 void RootWindowLayoutManager::OnWillRemoveWindowFromLayout(WmWindow* child) {}
 
 void RootWindowLayoutManager::OnWindowRemovedFromLayout(WmWindow* child) {}
 
 void RootWindowLayoutManager::OnChildWindowVisibilityChanged(WmWindow* child,
                                                              bool visible) {}
 
 void RootWindowLayoutManager::SetChildBounds(
     WmWindow* child,
     const gfx::Rect& requested_bounds) {
   child->SetBoundsDirect(requested_bounds);
 }
 
 }  // namespace wm
 }  // namespace ash