Evaluate MediaQueryLists on actual media changes only.

MediaQueryLists were re-evaluated for every styleResolverChanged(). The
evaluation of MediaQueryLists can only change when some media type or
features change. That is signalled through mediaQueryAffectingValueChanged().
Set m_evaluateMediaQueriesOnStyleRecalc there instead.

Since the media queries don't change this is not noticable through layout
or unit testing.

R=esprehn@chromium.org
BUG=382894

Review URL: https://codereview.chromium.org/322043008

git-svn-id: svn://svn.chromium.org/blink/trunk@176406 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/core/dom/Document.cpp

@@ -680,6 +680,7 @@ MediaQueryMatcher& Document::mediaQueryMatcher()
 
 void Document::mediaQueryAffectingValueChanged()
 {
+    m_evaluateMediaQueriesOnStyleRecalc = true;
     styleEngine()->clearMediaQueryRuleSetStyleSheets();
 }
 
@@ -3456,8 +3457,6 @@ void Document::styleResolverChanged(StyleResolverUpdateMode updateMode)
         m_pendingSheetLayout = IgnoreLayoutWithPendingSheets;
         renderView()->repaintViewAndCompositedLayers();
     }
-
-    m_evaluateMediaQueriesOnStyleRecalc = true;
 }
 
 void Document::styleResolverMayHaveChanged()