Loosening the coupling between WebRTC and //third_party/protobuf

webrtc/base/BUILD.gn

Index: webrtc/base/BUILD.gn
diff --git a/webrtc/base/BUILD.gn b/webrtc/base/BUILD.gn
index bf6d989027a0ba4757fad120b3523246668a66cb..341838506bb0e504c03e7c3925001055682ce43c 100644
--- a/webrtc/base/BUILD.gn
+++ b/webrtc/base/BUILD.gn
@@ -79,6 +79,17 @@ if (!rtc_build_ssl) {
   }
 }
 
+if (rtc_enable_protobuf) {

[kjellander_webrtc, 2017/03/16 13:29:54]

Hmm, I thought we would need to have this target available outside this
condition but as the linux_more_configs bot is passing (it does a build with
rtc_enable_protobuf=false) I guess it's not needed.

Or could it be that some of the targets including the header doesn't have GN
check enabled?

[mbonadei, 2017/03/16 14:48:57]

Mmmh... You are right! That's an awesome catch!

I checked the target webrtc/logging:rtc_event_log_impl and it is not triggering
the error even if we always include that header.
I am missing something here. Good that you spotted this. I will follow up.

+  source_set("protobuf_utils") {
+    sources = [
+      "protobuf_utils.h",
+    ]
+    public_deps = [
+      "//third_party/protobuf:protobuf_lite",
+    ]
+  }
+}
+
 # The subset of rtc_base approved for use outside of libjingle.
 rtc_static_library("rtc_base_approved") {
   defines = []