Get rid of use of "static const std::string".

BUG=angle:807
TEST=angle_unittests

Change-Id: Ifa4d713deeb25d52a7aafc362a7e4630024fd511
Reviewed-on: https://chromium-review.googlesource.com/225004
Tested-by: Zhenyao Mo <zmo@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
diff --git a/src/compiler/preprocessor/MacroExpander.cpp b/src/compiler/preprocessor/MacroExpander.cpp
index d7e0c83..69e2f39 100644
--- a/src/compiler/preprocessor/MacroExpander.cpp
+++ b/src/compiler/preprocessor/MacroExpander.cpp
@@ -194,8 +194,8 @@
 
         if (macro.predefined)
         {
-            static const std::string kLine = "__LINE__";
-            static const std::string kFile = "__FILE__";
+            const char kLine[] = "__LINE__";
+            const char kFile[] = "__FILE__";
 
             assert(replacements->size() == 1);
             Token& repl = replacements->front();