aura: Enable use_canvas_skia=1 on aura.

build/common.gypi

 # 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.
 
 # IMPORTANT:
 # Please don't directly include this file if you are building via gyp_chromium,
 # since gyp_chromium is automatically forcing its inclusion.
 {
   # Variables expected to be overriden on the GYP command line (-D) or by
   # ~/.gyp/include.gypi.
@@ skipping 407 matching lines @@
         }, {
           'linux_use_gold_flags%': 0,
         }],
 
         # Enable automation on platforms other than Android.
         ['OS=="android"', {
           'enable_automation%': 0,
         }, {
           'enable_automation%': 1,
         }],
+
+        # Use platform independent implementation of gfx::Canvas in Aura.

[Alexei Svitkine (slow), 2012/03/21 18:25:48]

Nit: Change this comment to:

# Enable Skia UI text drawing incrementally on different platforms.
# http://crbug.com/105550
#
# On Aura, this enables per-tile painting in the browser compositor.

+        ['use_aura==1', {
+          'use_canvas_skia%': 1,
+        }],
       ],
     },
 
     # Copy conditionally-set variables out one scope.
     'branding%': '<(branding)',
     'buildtype%': '<(buildtype)',
     'target_arch%': '<(target_arch)',
     'host_arch%': '<(host_arch)',
     'library%': 'static_library',
     'toolkit_views%': '<(toolkit_views)',
@@ skipping 2487 matching lines @@
     # settings in target dicts.  SYMROOT is a special case, because many other
     # Xcode variables depend on it, including variables such as
     # PROJECT_DERIVED_FILE_DIR.  When a source group corresponding to something
     # like PROJECT_DERIVED_FILE_DIR is added to a project, in order for the
     # files to appear (when present) in the UI as actual files and not red
     # red "missing file" proxies, the correct path to PROJECT_DERIVED_FILE_DIR,
     # and therefore SYMROOT, needs to be set at the project level.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }