Rearrange dependency to enable adding finch experiment in webrtc

third_party/libjingle/BUILD.gn

Index: third_party/libjingle/BUILD.gn
diff --git a/third_party/libjingle/BUILD.gn b/third_party/libjingle/BUILD.gn
index 5c462bcdcc31490715f5e2132b8fd7464fc77e56..532104199e7ed7a895ec4cdfbbef59185147bc84 100644
--- a/third_party/libjingle/BUILD.gn
+++ b/third_party/libjingle/BUILD.gn
@@ -256,7 +256,14 @@ static_library("libjingle") {
   }
 
   if (is_nacl) {
-    deps += [ "//native_client_sdk/src/libraries/nacl_io" ]
+    # For NACL, we have to add a default implementation for field_trail.
+    deps += [
+      "//native_client_sdk/src/libraries/nacl_io",
+      "//third_party/webrtc/system_wrappers:field_trial_default",
+    ]
+  } else {
+    # Otherwise, we just add the field_trial which redirects to base.
+    sources += [ "overrides/field_trial.cc" ]
   }
 
   configs += [ ":jingle_unexported_configs" ]