Make it possible to switch between two different versions of ANGLE.

gpu/gpu.gyp

 # 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.
 
 {
   'variables': {
     'nacl_win64_target': 0,
   },
   'includes': [
     'gpu_common.gypi',
@@ skipping 103 matching lines @@
       ],
     },
     {
       'target_name': 'gpu_unittests',
       'type': '<(gtest_target_type)',
       'dependencies': [
         '../base/base.gyp:base',
         '../base/third_party/dynamic_annotations/dynamic_annotations.gyp:dynamic_annotations',
         '../testing/gmock.gyp:gmock',
         '../testing/gtest.gyp:gtest',
-        '../third_party/angle/src/build_angle.gyp:translator_glsl',
+        '<(angle_path)/src/build_angle.gyp:translator_glsl',
         '../ui/gl/gl.gyp:gl',
         '../ui/ui.gyp:ui',
         'command_buffer/command_buffer.gyp:gles2_utils',
         'command_buffer_client',
         'command_buffer_common',
         'command_buffer_service',
         'gpu',
         'gpu_unittest_utils',
         'gles2_implementation_client_side_arrays',
         'gles2_cmd_helper',
@@ skipping 106 matching lines @@
       'msvs_disabled_warnings': [ 4267, ],
     },
     {
       'target_name': 'gl_tests',
       'type': '<(gtest_target_type)',
       'dependencies': [
         '../base/base.gyp:base',
         '../base/third_party/dynamic_annotations/dynamic_annotations.gyp:dynamic_annotations',
         '../testing/gmock.gyp:gmock',
         '../testing/gtest.gyp:gtest',
-        '../third_party/angle/src/build_angle.gyp:translator_glsl',
+        '<(angle_path)/src/build_angle.gyp:translator_glsl',
         '../ui/ui.gyp:ui',
         'command_buffer/command_buffer.gyp:gles2_utils',
         'command_buffer_client',
         'command_buffer_common',
         'command_buffer_service',
         'gpu',
         'gpu_unittest_utils',
         'gles2_implementation_client_side_arrays',
         'gles2_cmd_helper',
         #'gl_unittests',
@@ skipping 278 matching lines @@
             'input_shlib_path': '<(SHARED_LIB_DIR)/<(SHARED_LIB_PREFIX)gl_tests<(SHARED_LIB_SUFFIX)',
           },
           'includes': [
             '../build/apk_test.gypi',
           ],
         },
       ],
     }],
   ],
 }