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

ui/base/font_helper_chromeos.cc

Index: ui/base/font_helper_chromeos.cc
diff --git a/ui/base/font_helper_chromeos.cc b/ui/base/font_helper_chromeos.cc
index 6a77cf273d9ab6ed2cc0c9ea2fbd4abf459d30a5..dc7fb07c202987ecd767c606bb19d348ebe99494 100644
--- a/ui/base/font_helper_chromeos.cc
+++ b/ui/base/font_helper_chromeos.cc
@@ -10,8 +10,8 @@
 namespace ui {
 
 void ReplaceNotoSansWithRobotoIfEnabled(std::string* font_family) {
-  if (CommandLine::ForCurrentProcess()->
-      HasSwitch(switches::kEnableRobotoFontUI)) {
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kEnableRobotoFontUI)) {
     static const char kNotoSansUI[] = "Noto Sans UI";
     static const size_t kNotoSansUILen = arraysize(kNotoSansUI) - 1;
     std::string::size_type noto_position = font_family->find(kNotoSansUI);