Implement in-heap backing store for typed arrays.

include/v8.h

Index: include/v8.h
diff --git a/include/v8.h b/include/v8.h
index c56295ac78dd8a4c6561f97f12717e5972381520..a07d24dc485c055dd2a1a051f50bb5f599cf0976 100644
--- a/include/v8.h
+++ b/include/v8.h
@@ -5387,7 +5387,7 @@ class Internals {
   static const int kNullValueRootIndex = 7;
   static const int kTrueValueRootIndex = 8;
   static const int kFalseValueRootIndex = 9;
-  static const int kEmptyStringRootIndex = 135;
+  static const int kEmptyStringRootIndex = 144;
 
   static const int kNodeClassIdOffset = 1 * kApiPointerSize;
   static const int kNodeFlagsOffset = 1 * kApiPointerSize + 3;
@@ -5398,7 +5398,7 @@ class Internals {
   static const int kNodeIsIndependentShift = 4;
   static const int kNodeIsPartiallyDependentShift = 5;
 
-  static const int kJSObjectType = 0xb2;
+  static const int kJSObjectType = 0xbb;
   static const int kFirstNonstringType = 0x80;
   static const int kOddballType = 0x83;
   static const int kForeignType = 0x87;