Protect MediaValuesCached creation when RenderView is missing

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 57b7d9997a55edf6fe6e28573e867e3eafbcbfc6..f2572c755627dbbc8b6b7aec427f4abb3c9bdef1 100644
--- a/Source/core/css/MediaValues.cpp
+++ b/Source/core/css/MediaValues.cpp
@@ -30,18 +30,27 @@ PassRefPtr<MediaValues> MediaValues::createDynamicIfFrameExists(LocalFrame* fram
     return MediaValuesCached::create();
 }
 
+static float getEffectiveZoom(LocalFrame* frame)
+{
+    ASSERT(frame->document());
+    RenderStyle* style = (RenderStyle*)(frame->document()->renderView());

[eseidel, 2014/04/25 23:53:24]

Huh!?  That's not a style.

+    if (!style)
+        return 1.0;
+    return style->effectiveZoom();
+}
+
 int MediaValues::calculateViewportWidth(LocalFrame* frame) const
 {
-    ASSERT(frame && frame->view() && frame->document());
+    ASSERT(frame && frame->view());
     int viewportWidth = frame->view()->layoutSize(IncludeScrollbars).width();
-    return adjustForAbsoluteZoom(viewportWidth, frame->document()->renderView());
+    return adjustForAbsoluteZoom(viewportWidth, getEffectiveZoom(frame));
 }
 
 int MediaValues::calculateViewportHeight(LocalFrame* frame) const
 {
-    ASSERT(frame && frame->view() && frame->document());
+    ASSERT(frame && frame->view());
     int viewportHeight = frame->view()->layoutSize(IncludeScrollbars).height();
-    return adjustForAbsoluteZoom(viewportHeight, frame->document()->renderView());
+    return adjustForAbsoluteZoom(viewportHeight, getEffectiveZoom(frame));
 }
 
 int MediaValues::calculateDeviceWidth(LocalFrame* frame) const