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

chrome/browser/chrome_net_benchmarking_message_filter.cc

Index: chrome/browser/chrome_net_benchmarking_message_filter.cc
diff --git a/chrome/browser/chrome_net_benchmarking_message_filter.cc b/chrome/browser/chrome_net_benchmarking_message_filter.cc
index c3d5404ee1388c12c61ecb53dc00e08ad2a19e5c..d601bebdf9527eb0f093b14388941418ec82af6e 100644
--- a/chrome/browser/chrome_net_benchmarking_message_filter.cc
+++ b/chrome/browser/chrome_net_benchmarking_message_filter.cc
@@ -141,7 +141,8 @@ bool ChromeNetBenchmarkingMessageFilter::CheckBenchmarkingEnabled() const {
   static bool checked = false;
   static bool result = false;
   if (!checked) {
-    const CommandLine& command_line = *CommandLine::ForCurrentProcess();
+    const base::CommandLine& command_line =
+        *base::CommandLine::ForCurrentProcess();
     result = command_line.HasSwitch(switches::kEnableNetBenchmarking);
     checked = true;
   }