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

tools/gn/command_desc.cc

Index: tools/gn/command_desc.cc
diff --git a/tools/gn/command_desc.cc b/tools/gn/command_desc.cc
index 4cdc3f2be955411cd2a1d71b3511709e1a44fae5..b4e87b5e13cdc292c3395486e95c1c7fd2d5356c 100644
--- a/tools/gn/command_desc.cc
+++ b/tools/gn/command_desc.cc
@@ -102,7 +102,7 @@ void RecursivePrintDeps(const Target* target,
 }
 
 void PrintDeps(const Target* target, bool display_header) {
-  const CommandLine* cmdline = CommandLine::ForCurrentProcess();
+  const base::CommandLine* cmdline = base::CommandLine::ForCurrentProcess();
   Label toolchain_label = target->label().GetToolchainLabel();
 
   // Tree mode is separate.
@@ -407,7 +407,8 @@ template<typename T> void OutputRecursiveTargetConfig(
     const Target* target,
     const char* header_name,
     const std::vector<T>& (ConfigValues::* getter)() const) {
-  bool display_blame = CommandLine::ForCurrentProcess()->HasSwitch("blame");
+  bool display_blame =
+      base::CommandLine::ForCurrentProcess()->HasSwitch("blame");
 
   DescValueWriter<T> writer;
   std::ostringstream out;