Replace v8::Handle with v8::Local in core/testing/*

Source/core/testing/GCObservation.h

Index: Source/core/testing/GCObservation.h
diff --git a/Source/core/testing/GCObservation.h b/Source/core/testing/GCObservation.h
index 1c4831112c53d1eb14461565a03a560b65661614..b9fccb1d60df3f3f87efb510fddd7ae7559fd975 100644
--- a/Source/core/testing/GCObservation.h
+++ b/Source/core/testing/GCObservation.h
@@ -43,7 +43,7 @@ namespace blink {
 class GCObservation final : public GarbageCollectedFinalized<GCObservation>, public ScriptWrappable {
     DEFINE_WRAPPERTYPEINFO();
 public:
-    static GCObservation* create(v8::Handle<v8::Value> observedValue)
+    static GCObservation* create(v8::Local<v8::Value> observedValue)
     {
         return new GCObservation(observedValue);
     }
@@ -58,7 +58,7 @@ public:
     DEFINE_INLINE_TRACE() { }
 
 private:
-    explicit GCObservation(v8::Handle<v8::Value>);
+    explicit GCObservation(v8::Local<v8::Value>);
 
     ScopedPersistent<v8::Value> m_observed;
     bool m_collected;