Refactor the PlatformContext layer to have only one class.

chrome/browser/gtk/tabs/tab_renderer_gtk.cc

 // Copyright (c) 2009 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 "chrome/browser/gtk/tabs/tab_renderer_gtk.h"
 
+#include "app/gfx/canvas_paint.h"
 #include "app/l10n_util.h"
 #include "app/resource_bundle.h"
 #include "chrome/browser/browser.h"
 #include "chrome/browser/browser_theme_provider.h"
 #include "chrome/browser/gtk/custom_button.h"
 #include "chrome/browser/profile.h"
 #include "chrome/browser/tab_contents/tab_contents.h"
 #include "grit/app_resources.h"
 #include "grit/generated_resources.h"
 #include "grit/theme_resources.h"
@@ skipping 486 matching lines @@
     gtk_fixed_move(GTK_FIXED(tab_.get()), close_button_->widget(),
                    close_button_bounds_.x(), close_button_bounds_.y());
     gtk_widget_show(close_button_->widget());
   } else {
     gtk_widget_hide(close_button_->widget());
   }
 }
 
 void TabRendererGtk::PaintTab(GdkEventExpose* event) {
   gfx::CanvasPaint canvas(event, false);
-  if (canvas.isEmpty())
+  if (canvas.is_empty())
     return;
 
   // The tab is rendered into a windowless widget whose offset is at the
   // coordinate [x(), y()].  Translate by that offset so we can render at (0,0)
   // to match windows rendering metrics.
   canvas.TranslateInt(x(), y());
   Paint(&canvas);
 }
 
 void TabRendererGtk::PaintTabBackground(gfx::Canvas* canvas) {
@@ skipping 202 matching lines @@
   gfx::Font base_font = rb.GetFont(ResourceBundle::BaseFont);
   title_font_ = new gfx::Font(gfx::Font::CreateFont(base_font.FontName(), 10));
   title_font_height_ = title_font_->height();
 
   InitializeLoadingAnimationData(&rb, &loading_animation_data);
 
   crashed_fav_icon = rb.GetBitmapNamed(IDR_SAD_FAVICON);
 
   initialized_ = true;
 }