Remove kLatestVersion constant

Seems this is not used (anymore).

Change-Id: I3ac38799038231537d4fbc16428d1b523c7528b1
Reviewed-on: https://chromium-review.googlesource.com/728319Reviewed-by: Jeremy Roman <jbroman@chromium.org>
Commit-Queue: Rob Buis <rob.buis@samsung.com>
Cr-Commit-Position: refs/heads/master@{#510148}

third_party/WebKit/Source/bindings/core/v8/serialization/V8ScriptValueSerializer.h

@@ -43,8 +43,6 @@ class CORE_EXPORT V8ScriptValueSerializer
   RefPtr<SerializedScriptValue> Serialize(v8::Local<v8::Value>,
                                           ExceptionState&);
 
-  static const uint32_t kLatestVersion;
-
  protected:
   // Returns true if the DOM object was successfully written.
   // If false is returned and no more specific exception is thrown, a generic