Using relative path for GN for iOS.

webrtc/sdk/BUILD.gn

Index: webrtc/sdk/BUILD.gn
diff --git a/webrtc/sdk/BUILD.gn b/webrtc/sdk/BUILD.gn
index f4402c8b452b3a90b516cf44c829a849589c7102..9074fa8c83d84819a0784721cc05323605e8a46b 100644
--- a/webrtc/sdk/BUILD.gn
+++ b/webrtc/sdk/BUILD.gn
@@ -253,7 +253,7 @@ if (is_ios || (is_mac && mac_deployment_target == "10.7")) {
     "objc/Framework/Headers/WebRTC/UIDevice+RTCDevice.h",
     "objc/Framework/Headers/WebRTC/WebRTC.h",
   ]
-  if (is_mac) {
+  if (is_mac && !is_ios) {

[tkchin_webrtc, 2016/10/07 20:07:58]

why is this needed? 

[nicholss, 2016/10/07 20:42:29]

In GN, if is_ios us true, then is_mac is also true. So what this build file is
doing is setting the target called "rtc_sdk_framework_objc" under this is_mac
block and then overwriting it again in the is_ios block. 

I think it is good practice to be explicate about is_mac and is_ios so you do
not have unintentional side effects down the road. 

An alternative choice could be that we leave it in is_mac, delete the is_ios
target block and then make the minor modifications needed for ios inside the
target with additional is_ios checks, combining the two targets into one.

[tkchin_webrtc, 2016/10/07 20:48:42]

Is there a history behind that? It's odd that when target_os=ios mac is enabled
as well.

     mac_framework_bundle("rtc_sdk_framework_objc") {
       info_plist = "objc/Framework/Info.plist"
       output_name = "WebRTC"
@@ -267,8 +267,8 @@ if (is_ios || (is_mac && mac_deployment_target == "10.7")) {
 
       deps = [
         ":rtc_sdk_peerconnection_objc",
-        "//webrtc/system_wrappers:field_trial_default",
-        "//webrtc/system_wrappers:metrics_default",
+        "../system_wrappers:field_trial_default",
+        "../system_wrappers:metrics_default",
       ]
 
       libs = [
@@ -309,8 +309,8 @@ if (is_ios || (is_mac && mac_deployment_target == "10.7")) {
 
       deps = [
         ":rtc_sdk_peerconnection_objc",
-        "//webrtc/system_wrappers:field_trial_default",
-        "//webrtc/system_wrappers:metrics_default",
+        "../system_wrappers:field_trial_default",
+        "../system_wrappers:metrics_default",
       ]
 
       libs = [