[CSSMQ] Implemented support for the scan media feature.

Source/core/css/MediaQueryEvaluator.cpp

Index: Source/core/css/MediaQueryEvaluator.cpp
diff --git a/Source/core/css/MediaQueryEvaluator.cpp b/Source/core/css/MediaQueryEvaluator.cpp
index 3a223ea5ae2c8a8eb8e59003c4f3fcd80f813c74..d7e0fa8dc926552e04d78ecefc25e41c3ac49bfa 100644
--- a/Source/core/css/MediaQueryEvaluator.cpp
+++ b/Source/core/css/MediaQueryEvaluator.cpp
@@ -66,13 +66,10 @@ typedef HashMap<AtomicStringImpl*, EvalFunc> FunctionMap;
 static FunctionMap* gFunctionMap;
 
 /*
- * FIXME: following media features are not implemented: color_index, scan
+ * FIXME: following media features are not implemented: color_index
  *
  * color_index, min-color-index, max_color_index: It's unknown how to retrieve
  * the information if the display mode is indexed
- * scan: The "scan" media feature describes the scanning process of
- * tv output devices. It's unknown how to retrieve this information from
- * the platform
  */
 
 MediaQueryEvaluator::MediaQueryEvaluator(bool mediaFeatureResult)
@@ -744,6 +741,29 @@ static bool pointerMediaFeatureEval(CSSValue* value, RenderStyle*, Frame* frame,
         || (pointer == MousePointer && id == CSSValueFine);
 }
 
+static bool scanMediaFeatureEval(CSSValue* value, RenderStyle*, Frame* frame, MediaFeaturePrefix)
+{
+    String mediaType = frame->view()->mediaType();
+
+    // scan only applies to tv media.

[apavlov, 2013/05/15 11:29:41]

Blink mostly inherits the comment style from WebKit:
// Sentence-capitalized comment with a dot.

+    if (equalIgnoringCase(mediaType, "tv")) {

[apavlov, 2013/05/15 11:29:41]

Early returns are preferred, as they reduce code indentation and improve
readability:

// Scan only applies to tv media.
if (!equalIgnoringCase(mediaType, "tv"))
    return false;

// The rest of the code goes here...

+

[apavlov, 2013/05/15 11:29:41]

extra blank line

+        if (!value)
+            return true;
+
+        if (!value->isPrimitiveValue())
+            return false;
+
+        // If a platform interface supply progressive/interlace info for TVs in the

[apavlov, 2013/05/15 11:29:41]

supply -> supplies

+        // future, it needs to be handled here. For now, assume a modern TV with
+        // progressive display.
+        const int id = static_cast<CSSPrimitiveValue*>(value)->getIdent();
+        return id == CSSValueProgressive;
+    }
+
+    return false;
+}
+
 static void createFunctionMap()
 {
     // Create the table.