Oilpan: support GC event tracing following r360126.

third_party/WebKit/Source/platform/weborigin/OriginAccessEntryTest.cpp

Index: third_party/WebKit/Source/platform/weborigin/OriginAccessEntryTest.cpp
diff --git a/third_party/WebKit/Source/platform/weborigin/OriginAccessEntryTest.cpp b/third_party/WebKit/Source/platform/weborigin/OriginAccessEntryTest.cpp
index a014f6671b972165d8ea7571588bab45bb3cabe1..c689ab65914fba5e95a0d6a55e1c9ad73b5bf89c 100644
--- a/third_party/WebKit/Source/platform/weborigin/OriginAccessEntryTest.cpp
+++ b/third_party/WebKit/Source/platform/weborigin/OriginAccessEntryTest.cpp
@@ -79,6 +79,12 @@ public:
         RELEASE_ASSERT_NOT_REACHED();
     }
 
+    const unsigned char* getTraceCategoryEnabledFlag(const char* categoryName) override
+    {
+        static const unsigned char tracingIsDisabled = 0;
+        return &tracingIsDisabled;
+    }
+
     void setPublicSuffix(const blink::WebString& suffix)
     {
         m_suffixList.setPublicSuffix(suffix);