Fix build.

TBR=machenbach@chromium.org
NOTRY=true
NOTREECHECKS=true

Review URL: https://codereview.chromium.org/1150303002

Cr-Commit-Position: refs/heads/master@{#28590}

include/v8.h

@@ -6746,7 +6746,7 @@ class Internals {
   static const int kJSObjectHeaderSize = 3 * kApiPointerSize;
   static const int kFixedArrayHeaderSize = 2 * kApiPointerSize;
   static const int kContextHeaderSize = 2 * kApiPointerSize;
-  static const int kContextEmbedderDataIndex = 78;
+  static const int kContextEmbedderDataIndex = 79;
   static const int kFullStringRepresentationMask = 0x07;
   static const int kStringEncodingMask = 0x4;
   static const int kExternalTwoByteRepresentationTag = 0x02;