GTK: Step 1 of tab strip refresh.

chrome/browser/ui/gtk/cairo_cached_surface.h

 // 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.
 
 #ifndef CHROME_BROWSER_UI_GTK_CAIRO_CACHED_SURFACE_H_
 #define CHROME_BROWSER_UI_GTK_CAIRO_CACHED_SURFACE_H_
 #pragma once
 
 typedef struct _GdkPixbuf GdkPixbuf;
 typedef struct _cairo cairo_t;
@@ skipping 12 matching lines @@
 class CairoCachedSurface {
  public:
   CairoCachedSurface();
   ~CairoCachedSurface();
 
   // Whether this CairoCachedSurface owns a GdkPixbuf.
   bool valid() const {
     return pixbuf_;
   }
 
+  // Delete all our data.
+  void Reset();
+
   // The dimensions of the underlying pixbuf/surface. (or -1 if invalid.)
   int Width() const;
   int Height() const;
 
   // Sets the pixbuf that we pass to cairo. Calling UsePixbuf() only derefs the
   // current pixbuf and surface (if they exist). Actually transfering data to
   // the X server occurs at SetSource() time. Calling UsePixbuf() should only
   // be done once as it clears cached data from the X server.
   void UsePixbuf(GdkPixbuf* pixbuf);
 
   // Sets our pixbuf as the active surface starting at (x, y), uploading it in
   // case we don't have an X backed surface cached.
   void SetSource(cairo_t* cr, int x, int y);
 
+  // Performs a mask operation, using this surface as the alpha channel.
+  void MaskSource(cairo_t* cr, int x, int y);
+
   // Raw access to the pixbuf. May be NULL. Used for a few gdk operations
   // regarding window shaping.
   GdkPixbuf* pixbuf() { return pixbuf_; }
 
  private:
+  // Makes sure |surface_| is a valid thing that lives on the X server,
+  // uploading it if necessary.
+  void EnsureSurfaceValid(cairo_t* cr);
+
   // The source pixbuf.
   GdkPixbuf* pixbuf_;
 
   // Our cached surface. This should be a xlib surface so the data lives on the
   // server instead of on the client.
   cairo_surface_t* surface_;
 };
 
 #endif  // CHROME_BROWSER_UI_GTK_CAIRO_CACHED_SURFACE_H_