Generate TypedArrayInitialize builtin in hydrogen.

src/runtime.h

Index: src/runtime.h
diff --git a/src/runtime.h b/src/runtime.h
index 0e092002182b042297facdb8f91cde1898b5b80d..d6811e056e4d4f317b6d957380c27bcd1749e4b6 100644
--- a/src/runtime.h
+++ b/src/runtime.h
@@ -830,6 +830,22 @@ class Runtime : public AllStatic {
       Isolate* isolate,
       JSArrayBuffer* phantom_array_buffer);
 
+  enum TypedArrayId {
+    // arrayIds below should be synchromized with typedarray.js natives.
+    ARRAY_ID_UINT8 = 1,
+    ARRAY_ID_INT8 = 2,
+    ARRAY_ID_UINT16 = 3,
+    ARRAY_ID_INT16 = 4,
+    ARRAY_ID_UINT32 = 5,
+    ARRAY_ID_INT32 = 6,
+    ARRAY_ID_FLOAT32 = 7,
+    ARRAY_ID_FLOAT64 = 8,
+    ARRAY_ID_UINT8C = 9
+  };
+
+  static void ArrayIdToTypeAndSize(int array_id,
+      ExternalArrayType *type, size_t *element_size);
+
   // Helper functions used stubs.
   static void PerformGC(Object* result, Isolate* isolate);