Misc truncation fixes for gn builds with VS 2015

chrome/test/chromedriver/key_converter_unittest.cc

Index: chrome/test/chromedriver/key_converter_unittest.cc
diff --git a/chrome/test/chromedriver/key_converter_unittest.cc b/chrome/test/chromedriver/key_converter_unittest.cc
index 7cfcb52eb6ad8b39b7612f67b3622789d133218a..1916e1eda9546a7f5462f49f773215b8655edf57 100644
--- a/chrome/test/chromedriver/key_converter_unittest.cc
+++ b/chrome/test/chromedriver/key_converter_unittest.cc
@@ -342,7 +342,7 @@ TEST(KeyConverter, MAYBE_AllSpecialWebDriverKeysOnEnglishKeyboard) {
 #endif
       '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
       '*', '+', ',', '-', '.', '/'};
-  for (size_t i = 0; i <= 0x3D; ++i) {
+  for (base::char16 i = 0; i <= 0x3D; ++i) {
     if (i > 0x29 && i < 0x31)
       continue;
     base::string16 keys;