Test field trial group with startswith rather than equals.

webrtc/system_wrappers/source/field_trial_default.cc

Index: webrtc/system_wrappers/source/field_trial_default.cc
diff --git a/webrtc/system_wrappers/source/field_trial_default.cc b/webrtc/system_wrappers/source/field_trial_default.cc
index 0e2c286117a1a2cc96687c61b5f6c2483b0e4c37..7f1f772e4bb789f9e413a70721364ee913670196 100644
--- a/webrtc/system_wrappers/source/field_trial_default.cc
+++ b/webrtc/system_wrappers/source/field_trial_default.cc
@@ -53,6 +53,10 @@ std::string FindFullName(const std::string& name) {
   return std::string();
 }
 
+bool IsEnabled(const std::string& name) {
+  return FindFullName(name).find("Enabled") == 0;

[tommi, 2017/02/28 11:52:41]

Even though FindFullName currently forces creation of a std::string for every
static string, I don't think that's a good interface design.  Most (all?)
callers pass a static string, so that should be the best supported case.

Since FindFullName still requires creating a std::string, I'd prefer to keep
that conversion as an implementation detail of IsEnabled for now.  FindFullName
should be changed.

[sprang_webrtc, 2017/02/28 12:18:31]

That sounds good. 
Done.

+}
+
 // Optionally initialize field trial from a string.
 void InitFieldTrialsFromString(const char* trials_string) {
   trials_init_string = trials_string;