[es6] Introduce %ToInteger and %ToLength.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 431ead900cb7cae6727cea404061a2b0ca413f8a..7ea36cc4545d4a7c5f76c9d1394075fc81892791 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -1127,10 +1127,26 @@ class Object {
   // ES6 section 7.1.3 ToNumber
   MUST_USE_RESULT static MaybeHandle<Object> ToNumber(Handle<Object> input);
 
+  // ES6 section 7.1.4 ToInteger
+  MUST_USE_RESULT static MaybeHandle<Object> ToInteger(Isolate* isolate,
+                                                       Handle<Object> input);
+
+  // ES6 section 7.1.5 ToInt32
+  MUST_USE_RESULT static MaybeHandle<Object> ToInt32(Isolate* isolate,
+                                                     Handle<Object> input);
+
+  // ES6 section 7.1.6 ToUint32
+  MUST_USE_RESULT static MaybeHandle<Object> ToUint32(Isolate* isolate,
+                                                      Handle<Object> input);
+
   // ES6 section 7.1.12 ToString
   MUST_USE_RESULT static MaybeHandle<String> ToString(Isolate* isolate,
                                                       Handle<Object> input);
 
+  // ES6 section 7.1.15 ToLength
+  MUST_USE_RESULT static MaybeHandle<Object> ToLength(Isolate* isolate,
+                                                      Handle<Object> input);
+
   // ES6 section 7.3.9 GetMethod
   MUST_USE_RESULT static MaybeHandle<Object> GetMethod(
       Handle<JSReceiver> receiver, Handle<Name> name);