GTK: Refactor some things so GTK doesn't touch the on disk image cache.

chrome/browser/browser_theme_provider.h

 // 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.
 
 #ifndef CHROME_BROWSER_BROWSER_THEME_PROVIDER_H_
 #define CHROME_BROWSER_BROWSER_THEME_PROVIDER_H_
 
 #include <map>
 #include <string>
 #include <vector>
@@ skipping 243 matching lines @@
   // otherwise modified, or an application default.
   virtual SkBitmap* LoadThemeBitmap(int id);
 
   // Save the modified bitmap at image_cache_[id].
   virtual void SaveThemeBitmap(std::string resource_name, int id);
 
   // Clears the platform-specific caches. Do not call directly; it's called
   // from ClearCaches().
   virtual void FreePlatformCaches();
 
+  // The implementation of GenerateTabBackgroundBitmap(). That function also
+  // must be locked and touches caches; this function only deals with image
+  // generation.
+  SkBitmap* GenerateTabBackgroundBitmapImpl(int id);
+
   Profile* profile() { return profile_; }
 
   // Subclasses may need us to not use the on-disk image cache. The GTK
   // interface needs to generate some images itself.
   void force_process_images() { process_images_ = true; }
 
  private:
   typedef std::map<const int, std::string> ImageMap;
   typedef std::map<const std::string, SkColor> ColorMap;
   typedef std::map<const std::string, color_utils::HSL> TintMap;
@@ skipping 103 matching lines @@
   // If true, process all images; if false, just load from disk.
   bool process_images_;
 
   // Where we will store our generated images.
   FilePath image_dir_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserThemeProvider);
 };
 
 #endif  // CHROME_BROWSER_BROWSER_THEME_PROVIDER_H_