First cut at API for native Typed Arrays.

src/factory.cc

Index: src/factory.cc
diff --git a/src/factory.cc b/src/factory.cc
index f36006c1140db9bae82216352f4df5215d35735a..8dfab1803f165169b020a9c975cfb117b9826619 100644
--- a/src/factory.cc
+++ b/src/factory.cc
@@ -1056,6 +1056,54 @@ Handle<JSArrayBuffer> Factory::NewJSArrayBuffer() {
 }
 
 
+Handle<JSTypedArray> Factory::NewJSTypedArray(ExternalArrayType type) {
+  JSFunction* typed_array_fun;
+  Context* native_context = isolate()->context()->native_context();
+  switch (type) {
+    case kExternalUnsignedByteArray:
+      typed_array_fun = native_context->uint8_array_fun();
+      break;
+
+    case kExternalByteArray:
+      typed_array_fun = native_context->int8_array_fun();
+      break;
+
+    case kExternalUnsignedShortArray:
+      typed_array_fun = native_context->uint16_array_fun();
+      break;
+
+    case kExternalShortArray:
+      typed_array_fun = native_context->int16_array_fun();
+      break;
+
+    case kExternalUnsignedIntArray:
+      typed_array_fun = native_context->uint32_array_fun();
+      break;
+
+    case kExternalIntArray:
+      typed_array_fun = native_context->int32_array_fun();
+      break;
+
+    case kExternalFloatArray:
+      typed_array_fun = native_context->float_array_fun();
+      break;
+
+    case kExternalDoubleArray:
+      typed_array_fun = native_context->double_array_fun();
+      break;
+
+    default:
+      UNREACHABLE();
+      return Handle<JSTypedArray>();
+  }
+
+  CALL_HEAP_FUNCTION(
+      isolate(),
+      isolate()->heap()->AllocateJSObject(typed_array_fun),
+      JSTypedArray);
+}
+
+
 Handle<JSProxy> Factory::NewJSProxy(Handle<Object> handler,
                                     Handle<Object> prototype) {
   CALL_HEAP_FUNCTION(