Enable Media query evaluation in the preload scanner

Source/core/css/MediaQueryEvaluator.h

Index: Source/core/css/MediaQueryEvaluator.h
diff --git a/Source/core/css/MediaQueryEvaluator.h b/Source/core/css/MediaQueryEvaluator.h
index 4b3f9cff2d9f98bb120ead21bf02a399d3b67657..d94f8bdf2f72bb5a3b23e3cb356472269a8f4281 100644
--- a/Source/core/css/MediaQueryEvaluator.h
+++ b/Source/core/css/MediaQueryEvaluator.h
@@ -40,6 +40,64 @@ class RenderStyle;
 
 typedef WillBeHeapVector<RefPtrWillBeMember<MediaQueryResult> > MediaQueryResultList;
 typedef WillBePersistentHeapVector<RefPtrWillBeMember<MediaQueryResult> > WillBePersistentMediaQueryResultList;
+class Document;
+
+class MediaValues : public RefCounted<MediaValues> {

[abarth-chromium, 2014/03/24 19:43:31]

We prefer to have one class per file.  This class should go in a new
MediaValues.h file.  That makes it easier for people to find the definition of a
class.

+public:
+    // Should return a pointer that auto destructs when copied

[abarth-chromium, 2014/03/24 19:43:31]

I'm not sure what this comment means...  Is this a FIXME about what this code
should do in the future, or does it describe the current behavior of the code?

+    static PassRefPtr<MediaValues> create(Document*);
+    static PassRefPtr<MediaValues> copy(const MediaValues*);

[abarth-chromium, 2014/03/24 19:43:31]

Why isn't this a regular member function?

+
+    int getViewportWidth() { return m_viewportWidth; }
+    int getViewportHeight() { return m_viewportHeight; }
+    int getDeviceWidth() { return m_deviceWidth; }
+    int getDeviceHeight() { return m_deviceHeight; }
+    float getPixelRatio() { return m_pixelRatio; }
+    int getColorBitsPerComponent() { return m_colorBitsPerComponent; }
+    int getMonochromeBitsPerComponent() { return m_monochromeBitsPerComponent; }
+    int getPointer() { return m_pointer; }
+    int getDefaultFontSize() { return m_defaultFontSize; }
+    bool getThreeDEnabled() { return m_threeDEnabled; }
+    String getMediaType() { return m_mediaType; }

[abarth-chromium, 2014/03/24 19:43:31]

We generally omit the "get" prefix on getters.  For example:

int viewportWidth() const { return m_viewportWidth; }

Also, getters should be marked const.

+
+private:
+    MediaValues(int viewportWidth,

[eseidel, 2014/03/25 13:15:19]

I don't quite understand what's special about this class yet.  Should it just be
a struct instead of a class?  Will it have methods?

I guess it's read-only?  Then again that can be accomplished by passing it
around const...

+        int viewportHeight,
+        int deviceWidth,
+        int deviceHeight,
+        float pixelRatio,
+        int colorBitsPerComponent,
+        int monochromeBitsPerComponent,
+        int pointer,
+        int defaultFontSize,
+        int threeDEnabled,
+        String mediaType)
+        : m_viewportWidth(viewportWidth)
+        , m_viewportHeight(viewportHeight)
+        , m_deviceWidth(deviceWidth)
+        , m_deviceHeight(deviceHeight)
+        , m_pixelRatio(pixelRatio)
+        , m_colorBitsPerComponent(colorBitsPerComponent)
+        , m_monochromeBitsPerComponent(monochromeBitsPerComponent)
+        , m_pointer(pointer)
+        , m_defaultFontSize(defaultFontSize)
+        , m_threeDEnabled(threeDEnabled)
+        , m_mediaType(mediaType.isolatedCopy())
+    {
+    }
+
+    int m_viewportWidth;
+    int m_viewportHeight;
+    int m_deviceWidth;
+    int m_deviceHeight;
+    float m_pixelRatio;
+    int m_colorBitsPerComponent;
+    int m_monochromeBitsPerComponent;
+    int m_pointer;
+    int m_defaultFontSize;
+    bool m_threeDEnabled;
+    String m_mediaType;
+};
 
 /**
  * Class that evaluates css media queries as defined in
@@ -72,6 +130,10 @@ public:
     /** Creates evaluator which evaluates full media queries */
     MediaQueryEvaluator(const String& acceptedMediaType, LocalFrame*, RenderStyle*);
 
+    /** Creates evaluator which evaluates in a thread-safe manner a subset of media values
+     */

[abarth-chromium, 2014/03/24 19:43:31]

Can you convert these comments to C++ style comments (e.g., starting with //
rather than /*   )

+    MediaQueryEvaluator(const String& acceptedMediaType, const MediaValues* , bool mediaFeatureResult);

[abarth-chromium, 2014/03/24 19:43:31]

You've got an extra space between the * and the ,

+
     ~MediaQueryEvaluator();
 
     bool mediaTypeMatch(const String& mediaTypeToMatch) const;
@@ -88,6 +150,7 @@ private:
     LocalFrame* m_frame; // Not owned.

[abarth-chromium, 2014/03/24 19:43:31]

I'd remove this comment.  The frame obviously isn't owned.

     RefPtr<RenderStyle> m_style;
     bool m_expResult;
+    RefPtr<MediaValues> m_mediaValues;
 };
 
 } // namespace