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

tools/ipc_fuzzer/mutate/mutate.cc

Index: tools/ipc_fuzzer/mutate/mutate.cc
diff --git a/tools/ipc_fuzzer/mutate/mutate.cc b/tools/ipc_fuzzer/mutate/mutate.cc
index 3a42f4e96a65ffd1f83fa131cad3152d9a162103..68882d0e4351153a3c85bea163a57bbad0c0d488 100644
--- a/tools/ipc_fuzzer/mutate/mutate.cc
+++ b/tools/ipc_fuzzer/mutate/mutate.cc
@@ -655,9 +655,9 @@ void usage() {
 }  // namespace
 
 int MutateMain(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() != 2 || cmd->HasSwitch(kHelpSwitch)) {
     usage();