Revert of Oilpan: fix build after r201639. (patchset #1 id:1 of...

Revert of Oilpan: fix build after r201639. (patchset #1 id:1 of https://codereview.chromium.org/1312073003/ )

Reason for revert:
Not complete, reverting to reland.

Original issue's description:
> Oilpan: fix build after r201639.
> 
> TBR=oilpan-reviews
> BUG=none
> NOTRY=true
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=201647

TBR=oilpan-reviews@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=none

Review URL: https://codereview.chromium.org/1319623006

git-svn-id: svn://svn.chromium.org/blink/trunk@201648 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/core/css/ElementRuleCollector.h

@@ -58,7 +58,6 @@ public:
     const CSSStyleSheet* parentStyleSheet() const { return m_parentStyleSheet; }
     DEFINE_INLINE_TRACE()
     {
-        visitor->trace(m_ruleData);
         visitor->trace(m_parentStyleSheet);
     }