Loosening the coupling between WebRTC and //third_party/protobuf

webrtc/modules/audio_coding/BUILD.gn

 # Copyright (c) 2014 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.
 
 import("../../webrtc.gni")
 import("audio_coding.gni")
@@ skipping 64 matching lines @@
            "../../api/audio_codecs:audio_codecs_api",
            "../..:webrtc_common",
            "../../base:rtc_base_approved",
            "../../system_wrappers",
            ":audio_coding_module_typedefs",
            ":audio_encoder_interface",
            ":isac_common",
            ":isac_fix_c",
            ":neteq_decoder_enum",
          ] + audio_codec_deps
+
+  if (rtc_enable_protobuf) {
+    deps += [ "../../base:protobuf_utils" ]
+  }

[kwiberg-webrtc, 2017/03/22 10:03:23]

Why would you ever want a conditional dep on protobuf_utils? I thought the idea
was that protobuf_utils / protobuf_utils.h would always be there, but would be
empty if we don't have protobuf support.

In the .h and .cc files, you #include protobuf_utils.h unconditionally. That's
what you should do if you follow my advice, but if you want to do the
conditional deps like you do here, you need to protect those #includes with #if
WEBRTC_PROTOBUF_ENABLED. Which would be ugly... but if you don't do it, gn check
ought to complain if you build with rtc_enable_protobuf=false. (Did you try
that?)

[mbonadei, 2017/03/23 16:13:58]

Done and thanks for spotting this inconsistency. My bad, I was going in two
opposite directions.

Yes, I tried 'gn check' (both with rtc_enable_protobuf = true and
rtc_enable_protobuf = false) but it was somehow happy with all the conditions on
rtc_enable_protobuf. I guess that if the #include is not part of a defined
target it doesn't complain.

+
   defines = audio_codec_defines
 }
 
 config("audio_coding_config") {
   include_dirs = [
     "include",
     "../include",
   ]
 }
 
@@ skipping 735 matching lines @@
     "../../api/audio_codecs:audio_codecs_api",
     "../../base:rtc_base_approved",
     "../../base:rtc_numerics",
     "../../common_audio",
     "../../system_wrappers",
   ]
   public_deps = [
     ":webrtc_opus_c",
   ]
 
+  if (rtc_enable_protobuf) {
+    deps += [ "../../base:protobuf_utils" ]
+  }
+
   defines = audio_codec_defines
   if (rtc_opus_variable_complexity) {
     defines += [ "WEBRTC_OPUS_VARIABLE_COMPLEXITY=1" ]
   } else {
     defines += [ "WEBRTC_OPUS_VARIABLE_COMPLEXITY=0" ]
   }
 
   if (rtc_build_opus) {
     public_deps += [ rtc_opus_dir ]
   } else if (build_with_mozilla) {
@@ skipping 71 matching lines @@
     "../../base:rtc_base_approved",
     "../../common_audio",
     "../../logging:rtc_event_log_api",
     "../../system_wrappers",
   ]
 
   if (rtc_enable_protobuf) {
     deps += [
       ":ana_config_proto",
       ":ana_debug_dump_proto",
+      "../../base:protobuf_utils",
     ]
     defines = [ "WEBRTC_AUDIO_NETWORK_ADAPTOR_DEBUG_DUMP" ]
   }
 
   if (!build_with_chromium && is_clang) {
     # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).
     suppressed_configs += [ "//build/config/clang:find_bad_constructs" ]
   }
 }
 
@@ skipping 242 matching lines @@
     ]
     deps = [
       ":neteq_test_support",
       ":neteq_unittest_tools",
       ":webrtc_opus",
       "../..:webrtc_common",
       "../../base:rtc_base_approved",
       "../../system_wrappers:system_wrappers",
       "../../test:test_support",
     ]
+
+    if (rtc_enable_protobuf) {
+      deps += [ "../../base:protobuf_utils" ]
+    }
+
     if (!build_with_chromium && is_clang) {
       # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).
       suppressed_configs += [ "//build/config/clang:find_bad_constructs" ]
     }
   }
 
   rtc_source_set("acm_receive_test") {
     testonly = true
     sources = [
       "acm2/acm_receive_test.cc",
@@ skipping 119 matching lines @@
       ":isac",
       ":isac_fix",
       ":neteq",
       ":neteq_unittest_tools",
       "../../api/audio_codecs:audio_codecs_api",
       "../../common_audio",
       "../../test:test_main",
       "//testing/gtest",
     ]
 
+    if (rtc_enable_protobuf) {
+      deps += [ "../../base:protobuf_utils" ]
+    }
+
     data = audio_decoder_unittests_resources
 
     if (is_android) {
       deps += [ "//testing/android/native_test:native_test_native_code" ]
       shard_timeout = 900
     }
     if (is_ios) {
       deps += [ ":audio_decoder_unittests_bundle_data" ]
     }
   }  # audio_decoder_unittests
@@ skipping 753 matching lines @@
     defines = audio_coding_defines
 
     if (rtc_enable_protobuf) {
       defines += [
         "WEBRTC_AUDIO_NETWORK_ADAPTOR_DEBUG_DUMP",
         "WEBRTC_NETEQ_UNITTEST_BITEXACT",
       ]
       deps += [
         ":ana_config_proto",
         ":neteq_unittest_proto",
+        "../../base:protobuf_utils",
       ]
     }
 
     if (!build_with_chromium && is_clang) {
       # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).
       suppressed_configs += [ "//build/config/clang:find_bad_constructs" ]
     }
   }
 }
 
@@ skipping 13 matching lines @@
 # webrtc/api/audio_codecs:builtin_audio_decoder_factory instead.
 # TODO(kwiberg): Remove this.
 rtc_source_set("builtin_audio_decoder_factory") {
   sources = [
     "codecs/builtin_audio_decoder_factory.h",
   ]
   deps = [
     "../../api/audio_codecs:builtin_audio_decoder_factory",
   ]
 }