Use flag name without 'no' prefix only if it exists

webrtc/rtc_base/flags.cc

Index: webrtc/rtc_base/flags.cc
diff --git a/webrtc/rtc_base/flags.cc b/webrtc/rtc_base/flags.cc
index a245cecf1d4f9ef5aa38e4e159684a03e84809dd..b5697f162feb4da4a7255c6a86be981b35a94b58 100644
--- a/webrtc/rtc_base/flags.cc
+++ b/webrtc/rtc_base/flags.cc
@@ -149,7 +149,7 @@ void FlagList::SplitArgument(const char* arg,
     arg++;  // remove 1st '-'
     if (*arg == '-')
       arg++;  // remove 2nd '-'
-    if (arg[0] == 'n' && arg[1] == 'o') {
+    if (arg[0] == 'n' && arg[1] == 'o' && Lookup(arg + 2)) {
       arg += 2;  // remove "no"
       *is_bool = true;
     }

[kwiberg-webrtc, 2017/09/04 23:30:39]

Wait... what? Do we just *ignore* the "no" prefix? So that -foo and -nofoo mean
the same thing?

[oprypin_webrtc, 2017/09/05 06:54:16]

Yeah that also threw me off. This variable is more like... is_false, judging
from its usages.
I just re-checked that it works correctly.