Make callers of CommandLine use it via the base:: namespace.

tools/ipc_fuzzer/mutate/message_util.cc

Index: tools/ipc_fuzzer/mutate/message_util.cc
diff --git a/tools/ipc_fuzzer/mutate/message_util.cc b/tools/ipc_fuzzer/mutate/message_util.cc
index 4619af87e7271e87abccb75db0afb77ab27ae9fc..048f6e4350e1aa0e2b75f1662928bc42eedbcacf 100644
--- a/tools/ipc_fuzzer/mutate/message_util.cc
+++ b/tools/ipc_fuzzer/mutate/message_util.cc
@@ -73,9 +73,9 @@ bool MessageMatches(const IPC::Message* msg, const RE2& pattern) {
 }  // namespace
 
 int main(int argc, char** argv) {
-  CommandLine::Init(argc, argv);
-  CommandLine* cmd = CommandLine::ForCurrentProcess();
-  CommandLine::StringVector args = cmd->GetArgs();
+  base::CommandLine::Init(argc, argv);
+  base::CommandLine* cmd = base::CommandLine::ForCurrentProcess();
+  base::CommandLine::StringVector args = cmd->GetArgs();
 
   if (args.size() < 1 || args.size() > 2 || cmd->HasSwitch(kHelpSwitch)) {
     usage();