[builtins] Get rid of a few %_ClassOf uses.

src/runtime/runtime-typedarray.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/runtime/runtime-utils.h"
 
 #include "src/arguments.h"
 #include "src/factory.h"
 #include "src/messages.h"
 #include "src/objects-inl.h"
@@ skipping 415 matching lines @@
     return isolate->heap()->false_value();
   }
 
   Handle<JSTypedArray> obj(JSTypedArray::cast(args[0]));
   return isolate->heap()->ToBoolean(obj->GetBuffer()->is_shared() &&
                                     obj->type() != kExternalFloat32Array &&
                                     obj->type() != kExternalFloat64Array);
 }
 
 
+RUNTIME_FUNCTION(Runtime_IsSharedInteger32TypedArray) {
+  HandleScope scope(isolate);
+  DCHECK(args.length() == 1);
+  if (!args[0]->IsJSTypedArray()) {
+    return isolate->heap()->false_value();
+  }
+
+  Handle<JSTypedArray> obj(JSTypedArray::cast(args[0]));
+  return isolate->heap()->ToBoolean(obj->GetBuffer()->is_shared() &&
+                                    obj->type() == kExternalInt32Array);
+}
+
+
 RUNTIME_FUNCTION(Runtime_DataViewInitialize) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 4);
   CONVERT_ARG_HANDLE_CHECKED(JSDataView, holder, 0);
   CONVERT_ARG_HANDLE_CHECKED(JSArrayBuffer, buffer, 1);
   CONVERT_NUMBER_ARG_HANDLE_CHECKED(byte_offset, 2);
   CONVERT_NUMBER_ARG_HANDLE_CHECKED(byte_length, 3);
 
   DCHECK_EQ(v8::ArrayBufferView::kInternalFieldCount,
             holder->GetInternalFieldCount());
@@ skipping 235 matching lines @@
 DATA_VIEW_SETTER(Uint16, uint16_t)
 DATA_VIEW_SETTER(Int16, int16_t)
 DATA_VIEW_SETTER(Uint32, uint32_t)
 DATA_VIEW_SETTER(Int32, int32_t)
 DATA_VIEW_SETTER(Float32, float)
 DATA_VIEW_SETTER(Float64, double)
 
 #undef DATA_VIEW_SETTER
 }  // namespace internal
 }  // namespace v8