Don't try to remove the referrer from an empty page state

BUG=339790
R=marja@chromium.org

Review URL: https://codereview.chromium.org/166303003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251418 0039d316-1c4b-4281-b951-d872f2087c98

components/sessions/serialized_navigation_entry_unittest.cc

@@ -325,6 +325,9 @@ TEST(SerializedNavigationEntryTest, Sanitize) {
   EXPECT_EQ(kSearchTerms, navigation.search_terms());
   EXPECT_EQ(kFaviconURL, navigation.favicon_url());
   EXPECT_EQ(kHttpStatusCode, navigation.http_status_code());
+
+  content::PageState empty_state;
+  EXPECT_TRUE(empty_state.Equals(empty_state.RemoveReferrer()));
 }
 
 }  // namespace

content/public/common/page_state.cc

@@ -151,6 +151,9 @@ PageState PageState::RemoveScrollOffset() const {
 }
 
 PageState PageState::RemoveReferrer() const {
+  if (data_.empty())
+    return *this;
+
   ExplodedPageState state;
   if (!DecodePageState(data_, &state))
     return PageState();  // Oops!