Change scanner buffers to not use utf-8.

src/heap.cc

Index: src/heap.cc
diff --git a/src/heap.cc b/src/heap.cc
index cbb021cd154da807e10d1eff9b0779dfe3c32183..44229f09b3d32245cde92475a003168b17ca03e0 100644
--- a/src/heap.cc
+++ b/src/heap.cc
@@ -4013,6 +4013,36 @@ MaybeObject* Heap::LookupSymbol(Vector<const char> string) {
 }
 
 
+MaybeObject* Heap::LookupAsciiSymbol(Vector<const char> string) {
+  Object* symbol = NULL;
+  Object* new_table;
+  { MaybeObject* maybe_new_table =
+        symbol_table()->LookupAsciiSymbol(string, &symbol);
+    if (!maybe_new_table->ToObject(&new_table)) return maybe_new_table;
+  }
+  // Can't use set_symbol_table because SymbolTable::cast knows that
+  // SymbolTable is a singleton and checks for identity.
+  roots_[kSymbolTableRootIndex] = new_table;
+  ASSERT(symbol != NULL);
+  return symbol;
+}
+
+
+MaybeObject* Heap::LookupTwoByteSymbol(Vector<const uc16> string) {
+  Object* symbol = NULL;
+  Object* new_table;
+  { MaybeObject* maybe_new_table =
+        symbol_table()->LookupTwoByteSymbol(string, &symbol);
+    if (!maybe_new_table->ToObject(&new_table)) return maybe_new_table;
+  }
+  // Can't use set_symbol_table because SymbolTable::cast knows that
+  // SymbolTable is a singleton and checks for identity.
+  roots_[kSymbolTableRootIndex] = new_table;
+  ASSERT(symbol != NULL);
+  return symbol;
+}
+
+
 MaybeObject* Heap::LookupSymbol(String* string) {
   if (string->IsSymbol()) return string;
   Object* symbol = NULL;