Convert //tools to use std::unique_ptr

tools/gn/exec_process.cc

Index: tools/gn/exec_process.cc
diff --git a/tools/gn/exec_process.cc b/tools/gn/exec_process.cc
index e5ab248af8a9c336535e8029e7f93443759528b5..8a47fbe2053ced320640b2ada441b0ab774c1012 100644
--- a/tools/gn/exec_process.cc
+++ b/tools/gn/exec_process.cc
@@ -6,10 +6,11 @@
 
 #include <stddef.h>
 
+#include <memory>
+
 #include "base/command_line.h"
 #include "base/files/file_util.h"
 #include "base/logging.h"
-#include "base/memory/scoped_ptr.h"
 #include "base/process/kill.h"
 #include "base/process/launch.h"
 #include "base/process/process.h"
@@ -157,7 +158,7 @@ bool ExecProcess(const base::CommandLine& cmdline,
   int out_fd[2], err_fd[2];
   pid_t pid;
   base::InjectiveMultimap fd_shuffle1, fd_shuffle2;
-  scoped_ptr<char*[]> argv_cstr(new char*[argv.size() + 1]);
+  std::unique_ptr<char* []> argv_cstr(new char*[argv.size() + 1]);
 
   fd_shuffle1.reserve(3);
   fd_shuffle2.reserve(3);