adding DiscardableMemory preferences for deferred image decoding

webkit/glue/webpreferences.h

 // 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.
 //
 // A struct for managing webkit's settings.
 //
 // Adding new values to this class probably involves updating
 // WebKit::WebSettings, content/common/view_messages.h, browser/tab_contents/
 // render_view_host_delegate_helper.cc, and browser/profiles/profile.cc.
 
@@ skipping 132 matching lines @@
   bool device_supports_touch;
   bool device_supports_mouse;
   bool touch_adjustment_enabled;
   int default_tile_width;
   int default_tile_height;
   int max_untiled_layer_width;
   int max_untiled_layer_height;
   bool fixed_position_creates_stacking_context;
   bool sync_xhr_in_documents_enabled;
   bool deferred_image_decoding_enabled;
+  int discardable_memory_limit_mb;
+  int discardable_memory_entry_limit;
   bool should_respect_image_orientation;
   int number_of_cpu_cores;
   EditingBehavior editing_behavior;
   bool supports_multiple_windows;
   bool viewport_enabled;
 
   // This flags corresponds to a Page's Settings' setCookieEnabled state. It
   // only controls whether or not the "document.cookie" field is properly
   // connected to the backing store, for instance if you wanted to be able to
   // define custom getters and setters from within a unique security content
@@ skipping 12 matching lines @@
   // the embedder to use the same default value.
   WebPreferences();
   ~WebPreferences();
 
   void Apply(WebKit::WebView* web_view) const;
 };
 
 }  // namespace webkit_glue
 
 #endif  // WEBKIT_GLUE_WEBPREFERENCES_H__