Change Page::m_mainFrame to be a Frame.

Source/core/css/MediaValues.cpp

Index: Source/core/css/MediaValues.cpp
diff --git a/Source/core/css/MediaValues.cpp b/Source/core/css/MediaValues.cpp
index b0b6a80b4cba943b28d1157e8e615c0a73b28f3c..e12af99d1a7a1a03ee8b0e8dad6b8935cb5952c3 100644
--- a/Source/core/css/MediaValues.cpp
+++ b/Source/core/css/MediaValues.cpp
@@ -73,10 +73,13 @@ float MediaValues::calculateDevicePixelRatio(LocalFrame* frame) const
     return frame->devicePixelRatio();
 }
 
+// FIXME: Broken for OOPI. These checks can't assume there will be a top level
+// FrameView.
 int MediaValues::calculateColorBitsPerComponent(LocalFrame* frame) const
 {
     ASSERT(frame && frame->page() && frame->page()->mainFrame());
-    if (screenIsMonochrome(frame->page()->mainFrame()->view()))
+    if (!frame->page()->mainFrame()->isLocalFrame()
+        || screenIsMonochrome(toLocalFrame(frame->page()->mainFrame())->view()))
         return 0;
     return screenDepthPerComponent(frame->view());
 }
@@ -84,9 +87,10 @@ int MediaValues::calculateColorBitsPerComponent(LocalFrame* frame) const
 int MediaValues::calculateMonochromeBitsPerComponent(LocalFrame* frame) const
 {
     ASSERT(frame && frame->page() && frame->page()->mainFrame());
-    if (screenIsMonochrome(frame->page()->mainFrame()->view()))
-        return screenDepthPerComponent(frame->view());
-    return 0;
+    if (!frame->page()->mainFrame()->isLocalFrame()
+        || !screenIsMonochrome(toLocalFrame(frame->page()->mainFrame())->view()))
+        return 0;
+    return screenDepthPerComponent(frame->view());
 }
 
 int MediaValues::calculateDefaultFontSize(LocalFrame* frame) const