iOS: Include legacy objc API in all.gyp + fix H264 libyuv dependency

webrtc/modules/video_coding/codecs/h264/h264.gypi

 # Copyright (c) 2015 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': [
@@ skipping 44 matching lines @@
         'include/h264.h',
       ],
     }, # webrtc_h264
   ],
   'conditions': [
     ['OS=="ios"', {
       'targets': [
         {
           'target_name': 'webrtc_h264_video_toolbox',
           'type': 'static_library',
-          'dependencies': [
-            '<(DEPTH)/third_party/libyuv/libyuv.gyp:libyuv',
-          ],
           'link_settings': {
             'xcode_settings': {
               'OTHER_LDFLAGS': [
                 '-framework CoreFoundation',
                 '-framework CoreMedia',
                 '-framework CoreVideo',
                 '-framework VideoToolbox',
               ],
             },
           },
           'sources': [
             'h264_video_toolbox_decoder.cc',
             'h264_video_toolbox_decoder.h',
             'h264_video_toolbox_encoder.cc',
             'h264_video_toolbox_encoder.h',
             'h264_video_toolbox_nalu.cc',
             'h264_video_toolbox_nalu.h',
           ],
+          'conditions': [
+            ['build_libyuv==1', {
+              'dependencies': ['<(DEPTH)/third_party/libyuv/libyuv.gyp:libyuv'],
+            }],
+          ],
         }, # webrtc_h264_video_toolbox
       ], # targets
     }], # OS=="ios"
   ], # conditions
 }