Fix memory leak.

chrome/browser/history/top_sites.cc

Index: chrome/browser/history/top_sites.cc
diff --git a/chrome/browser/history/top_sites.cc b/chrome/browser/history/top_sites.cc
index d22fc6b4662ab2d8b358301e8d63f15837dd60af..348ab7b6730e655c7556de4f9bad112030ef8ad7 100644
--- a/chrome/browser/history/top_sites.cc
+++ b/chrome/browser/history/top_sites.cc
@@ -654,8 +654,7 @@ void TopSites::AddBlacklistedURL(const GURL& url) {
 }
 
 bool TopSites::IsBlacklisted(const GURL& url) {
-  Value* dummy = Value::CreateNullValue();
-  bool result = blacklist_->GetWithoutPathExpansion(GetURLHash(url), &dummy);
+  bool result = blacklist_->HasKey(GetURLHash(url));
   return result;
 }