Protect MediaValuesCached creation when RenderView is missing

Source/core/css/MediaValues.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/css/MediaValues.h"
 
 #include "core/css/CSSHelper.h"
 #include "core/css/MediaValuesCached.h"
 #include "core/css/MediaValuesDynamic.h"
@@ skipping 12 matching lines @@
 
 namespace WebCore {
 
 PassRefPtr<MediaValues> MediaValues::createDynamicIfFrameExists(LocalFrame* frame)
 {
     if (frame)
         return MediaValuesDynamic::create(frame);
     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
 {
     ASSERT(frame && frame->view() && frame->settings() && frame->host());
     int deviceWidth = static_cast<int>(screenRect(frame->view()).width());
     if (frame->settings()->reportScreenSizeInPhysicalPixelsQuirk())
         deviceWidth = lroundf(deviceWidth * frame->host()->deviceScaleFactor());
     return deviceWidth;
 }
@@ skipping 140 matching lines @@
     default:
         return false;
     }
 
     ASSERT(factor > 0);
     result = roundForImpreciseConversion<int>(value*factor);
     return true;
 }
 
 } // namespace