clang/win: Let some chromium_code targets build with -Wextra.

chrome/installer/util/app_command.cc

Index: chrome/installer/util/app_command.cc
diff --git a/chrome/installer/util/app_command.cc b/chrome/installer/util/app_command.cc
index 0d6be906888589ab5d11b97c33324ab3c8bbcdcf..66242b5fe325f8b97c6c6b16c3746e62c6a1df29 100644
--- a/chrome/installer/util/app_command.cc
+++ b/chrome/installer/util/app_command.cc
@@ -57,7 +57,7 @@ bool AppCommand::Initialize(const base::win::RegKey& key) {
 
   command_line_.swap(cmd_line);
 
-  for (int i = 0; i < arraysize(kNameBoolVars); ++i) {
+  for (size_t i = 0; i < arraysize(kNameBoolVars); ++i) {
     DWORD value = 0;  // Set default to false.
     // Note: ReadValueDW only modifies out param on success.
     key.ReadValueDW(kNameBoolVars[i].name, &value);
@@ -83,7 +83,7 @@ void AppCommand::AddWorkItems(HKEY predefined_root,
                                     true)
       ->set_log_message("setting AppCommand CommandLine registry value");
 
-  for (int i = 0; i < arraysize(kNameBoolVars); ++i) {
+  for (size_t i = 0; i < arraysize(kNameBoolVars); ++i) {
     const wchar_t* var_name = kNameBoolVars[i].name;
     bool var_data = this->*(kNameBoolVars[i].data);