Polymorphic inlining for some recognized methods in the optimizing compiler.

runtime/vm/intermediate_language.h

Index: runtime/vm/intermediate_language.h
===================================================================
--- runtime/vm/intermediate_language.h	(revision 25997)
+++ runtime/vm/intermediate_language.h	(working copy)
@@ -132,6 +132,11 @@
 
 // A list of core function that should always be inlined.
 #define INLINE_WHITE_LIST(V)                                                   \
+  V(_ObjectArray, get:length, ObjectArrayLength, 405297088)                    \
+  V(_ImmutableArray, get:length, ImmutableArrayLength, 433698233)              \
+  V(_TypedList, get:length, TypedDataLength, 1004567191)                       \
+  V(_GrowableObjectArray, get:length, GrowableArrayLength, 725548050)          \
+  V(_StringBase, get:length, StringBaseLength, 320803993)                      \
   V(ListIterator, moveNext, ListIteratorMoveNext, 203118278)                   \
   V(_GrowableObjectArray, get:iterator, GrowableArrayIterator, 810824939)      \
   V(_GrowableObjectArray, forEach, GrowableArrayForEach, 619038738)
@@ -2695,6 +2700,8 @@
     return instance_call()->PushArgumentAt(index);
   }
 
+  bool HasRecognizedTarget() const;
+
   DECLARE_INSTRUCTION(PolymorphicInstanceCall)
 
   const ICData& ic_data() const { return ic_data_; }