Remove PlatformMouseEvent::m_modifierFlags member.

Source/core/page/Chrome.cpp

Index: Source/core/page/Chrome.cpp
diff --git a/Source/core/page/Chrome.cpp b/Source/core/page/Chrome.cpp
index dce9bbb2f2da2e50a6fdd2377d68edbf23f24e71..af2fe7635e2d3de55c1a8000b7f1777e291d981c 100644
--- a/Source/core/page/Chrome.cpp
+++ b/Source/core/page/Chrome.cpp
@@ -277,13 +277,13 @@ IntRect Chrome::windowResizerRect() const
     return m_client->windowResizerRect();
 }
 
-void Chrome::mouseDidMoveOverElement(const HitTestResult& result, unsigned modifierFlags)
+void Chrome::mouseDidMoveOverElement(const HitTestResult& result)
 {
     if (result.innerNode()) {
         if (result.innerNode()->document().isDNSPrefetchEnabled())
             prefetchDNS(result.absoluteLinkURL().host());
     }
-    m_client->mouseDidMoveOverElement(result, modifierFlags);
+    m_client->mouseDidMoveOverElement(result);
 }
 
 void Chrome::setToolTip(const HitTestResult& result)