GN: Move towards only using / on Windows

tools/gn/escape.cc

Index: tools/gn/escape.cc
diff --git a/tools/gn/escape.cc b/tools/gn/escape.cc
index e10e24a2b68c48f6a5c0454e33ecd036879320e0..763b2c6d5fdac480d5cea424c94c845f28320cde 100644
--- a/tools/gn/escape.cc
+++ b/tools/gn/escape.cc
@@ -45,11 +45,7 @@ void EscapeStringToString(const base::StringPiece& str,
     } else if (str[i] == '\'' && (options.mode & ESCAPE_JSON)) {
       dest->push_back('\\');
       dest->push_back('\'');
-#if defined(OS_WIN)
-    } else if (str[i] == '/' && options.convert_slashes) {
-      // Convert slashes on Windows if requested.
-      dest->push_back('\\');
-#else
+#if !defined(OS_WIN)
     } else if (str[i] == '\\' && (options.mode & ESCAPE_SHELL)) {
       // For non-Windows shell, escape backslashes.
       dest->push_back('\\');