Adds support for saving favicon size into history database.

ui/gfx/size_base.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.
 
 #ifndef UI_GFX_SIZE_BASE_H_
 #define UI_GFX_SIZE_BASE_H_
 
 #include <string>
 
 #include "build/build_config.h"
@@ skipping 33 matching lines @@
   void set_height(Type height);
 
   bool operator==(const Class& s) const {
     return width_ == s.width_ && height_ == s.height_;
   }
 
   bool operator!=(const Class& s) const {
     return !(*this == s);
   }
 
+  // A size is less than another size if its width is less than the |other|
+  // size's width. If the widths are equal, then the size with the smallest
+  // height is less than the other. The comparison is required to uses Sizes in
+  // sets and sorted vectors.
+  bool operator<(const Class& other) const {
+    return (width_ == other.width_) ?
+        height_ < other.height_ : width_ < other.width_;
+  }
+
   bool IsEmpty() const {
     // Size doesn't allow negative dimensions, so testing for 0 is enough.
     return (width_ == 0) || (height_ == 0);
   }
 
  protected:
   SizeBase(Type width, Type height);
   // Destructor is intentionally made non virtual and protected.
   // Do not make this public.
   ~SizeBase();
 
  private:
   Type width_;
   Type height_;
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_SIZE_BASE_H_