GN: Fix test_support_unittests and MIPS compile issue.

webrtc/test/metrics.gyp

-# Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
-#
-# Use of this source code is governed by a BSD-style license
-# that can be found in the LICENSE file in the root of the source
-# tree. An additional intellectual property rights grant can be found
-# in the file PATENTS.  All contributing project authors may
-# be found in the AUTHORS file in the root of the source tree.
-
-{
-  'includes': [
-    '../build/common.gypi',
-  ],
-  'targets': [
-    {
-      # The metrics code must be kept in its own GYP file in order to
-      # avoid a circular dependency error due to the dependency on libyuv.
-      # If the code would be put in test.gyp a circular dependency error during
-      # GYP generation would occur, because the libyuv.gypi unittest target
-      # depends on test_support_main. See issue #160 for more info.

[kjellander_webrtc, 2016/08/23 06:29:54]

I believe this dependency problem no longer exists.

I double-checked by commenting
https://cs.chromium.org/chromium/src/third_party/webrtc/build/gyp_webrtc.py?r...
and run the script with/without this patch. Both runs showed 14 cycles.

-      'target_name': 'metrics',
-      'type': 'static_library',
-      'dependencies': [
-        '<(webrtc_root)/common_video/common_video.gyp:common_video',
-        '<(webrtc_root)/system_wrappers/system_wrappers.gyp:system_wrappers',
-      ],
-      'sources': [
-        'testsupport/metrics/video_metrics.h',
-        'testsupport/metrics/video_metrics.cc',
-      ],
-    },
-  ], # targets
-}