[wasm][asm.js] Adding custom asm.js lexer.

src/parsing/scanner-character-streams.h

Index: src/parsing/scanner-character-streams.h
diff --git a/src/parsing/scanner-character-streams.h b/src/parsing/scanner-character-streams.h
index 291765cee49f6b8adf4c297a74151e3d0fcefeb7..9f7d2bd5fb5c8b05b27bb2799986dff3f23e9064 100644
--- a/src/parsing/scanner-character-streams.h
+++ b/src/parsing/scanner-character-streams.h
@@ -6,6 +6,7 @@
 #define V8_PARSING_SCANNER_CHARACTER_STREAMS_H_
 
 #include "include/v8.h"  // for v8::ScriptCompiler
+#include "src/globals.h"
 
 namespace v8 {
 namespace internal {
@@ -16,7 +17,7 @@ class Utf16CharacterStream;
 class RuntimeCallStats;
 class String;
 
-class ScannerStream {
+class V8_EXPORT_PRIVATE ScannerStream {
  public:
   static Utf16CharacterStream* For(Handle<String> data);
   static Utf16CharacterStream* For(Handle<String> data, int start_pos,