Adds an RTree data structure to gfx/geometry

ui/gfx/gfx.gyp

 # Copyright (c) 2013 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.
 
 {
   'variables': {
     'chromium_code': 1,
   },
   'targets': [
     {
@@ skipping 29 matching lines @@
         'geometry/quad_f.cc',
         'geometry/quad_f.h',
         'geometry/rect.cc',
         'geometry/rect.h',
         'geometry/rect_base.h',
         'geometry/rect_base_impl.h',
         'geometry/rect_conversions.cc',
         'geometry/rect_conversions.h',
         'geometry/rect_f.cc',
         'geometry/rect_f.h',
+        'geometry/r_tree.cc',
+        'geometry/r_tree.h',
         'geometry/safe_integer_conversions.h',
         'geometry/size.cc',
         'geometry/size.h',
         'geometry/size_base.h',
         'geometry/size_conversions.cc',
         'geometry/size_conversions.h',
         'geometry/size_f.cc',
         'geometry/size_f.h',
         'geometry/vector2d.cc',
         'geometry/vector2d.h',
@@ skipping 396 matching lines @@
         'color_utils_unittest.cc',
         'display_unittest.cc',
         'geometry/box_unittest.cc',
         'geometry/cubic_bezier_unittest.cc',
         'geometry/insets_unittest.cc',
         'geometry/matrix3_unittest.cc',
         'geometry/point_unittest.cc',
         'geometry/point3_unittest.cc',
         'geometry/quad_unittest.cc',
         'geometry/rect_unittest.cc',
+        'geometry/r_tree_unittest.cc',
         'geometry/safe_integer_conversions_unittest.cc',
         'geometry/size_unittest.cc',
         'geometry/vector2d_unittest.cc',
         'geometry/vector3d_unittest.cc',
         'range/range_mac_unittest.mm',
         'range/range_unittest.cc',
         'range/range_win_unittest.cc',
         'shadow_value_unittest.cc',
         'skbitmap_operations_unittest.cc',
         'skrect_conversion_unittest.cc',
@@ skipping 80 matching lines @@
             'x/x11_error_tracker.cc',
             'x/x11_error_tracker.h',
             'x/x11_types.cc',
             'x/x11_types.h',
           ],
         },
       ]
     }],
   ],
 }