Rework tree APIs to reflect Google style and more const-correctness....

views/layout/fill_layout.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 "views/layout/fill_layout.h"
 
 #include "base/logging.h"
 
 namespace views {
 
 FillLayout::FillLayout() {
 }
 
 FillLayout::~FillLayout() {
 }
 
 void FillLayout::Layout(View* host) {
-  if (host->GetChildViewCount() == 0)
+  if (!host->has_children())
     return;
 
   View* frame_view = host->GetChildViewAt(0);
   frame_view->SetBounds(0, 0, host->width(), host->height());
 }
 
 gfx::Size FillLayout::GetPreferredSize(View* host) {
-  DCHECK(host->GetChildViewCount() == 1);
+  DCHECK(host->child_count() == 1);
   return host->GetChildViewAt(0)->GetPreferredSize();
 }
 
 }  // namespace views