Split property priority functions out of StyleResolver.

Source/core/css/resolver/StylePropertyRange.h

Index: Source/core/css/resolver/StylePropertyRange.h
diff --git a/Source/core/css/resolver/StylePropertyRange.h b/Source/core/css/resolver/StylePropertyRange.h
new file mode 100644
index 0000000000000000000000000000000000000000..c8946ff183f46d04d1418174a78d27df3e117c36
--- /dev/null
+++ b/Source/core/css/resolver/StylePropertyRange.h
@@ -0,0 +1,76 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.

[Timothy Loh, 2015/02/01 22:17:09]

2015 ;)

[andersr, 2015/02/02 15:51:24]

Done.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef StylePropertyRange_h
+#define StylePropertyRange_h
+
+#include "core/CSSPropertyNames.h"
+
+namespace blink {
+
+enum StyleApplicationPass {

[Timothy Loh, 2015/02/01 22:17:09]

Nit-picking about names since we're already touching these lines, something like
CSSPropertyPriority, {High,Low}PropertyPriority, CSSPropertyPriorityData makes
more sense to me.

[andersr, 2015/02/02 15:51:24]

Done.

+    HighPriorityProperties,
+    LowPriorityProperties
+};
+
+class StylePropertyRange {
+public:
+    template <StyleApplicationPass pass>
+    static inline CSSPropertyID firstCSSPropertyId();
+
+    template <StyleApplicationPass pass>
+    static inline CSSPropertyID lastCSSPropertyId();
+
+    template <StyleApplicationPass pass>
+    static inline bool isPropertyForPass(CSSPropertyID property)
+    {
+        return firstCSSPropertyId<pass>() <= property && property <= lastCSSPropertyId<pass>();
+    }
+};
+
+// This method returns the first CSSPropertyId of high priority properties.

[Timothy Loh, 2015/02/01 22:17:09]

I'd describe property priority above the enum up top and remove the rest of the
comments.

[andersr, 2015/02/02 15:51:24]

Done.

+// Other properties can depend on high priority properties. For example,
+// border-color property with currentColor value depends on color property.
+// All high priority properties are obtained by using
+// firstCSSPropertyId<HighPriorityProperties> and
+// lastCSSPropertyId<HighPriorityProperties>.
+template<>
+inline CSSPropertyID StylePropertyRange::firstCSSPropertyId<HighPriorityProperties>()
+{
+    static_assert(CSSPropertyColor == firstCSSProperty, "CSSPropertyColor should be the first high priority property");
+    return CSSPropertyColor;
+}
+
+// This method returns the last CSSPropertyId of high priority properties.
+template<>
+inline CSSPropertyID StylePropertyRange::lastCSSPropertyId<HighPriorityProperties>()
+{
+    static_assert(CSSPropertyZoom == CSSPropertyColor + 16, "CSSPropertyZoom should be the end of the high priority property range");
+    static_assert(CSSPropertyTextRendering == CSSPropertyZoom - 1, "CSSPropertyTextRendering should be immediately before CSSPropertyZoom");
+    return CSSPropertyZoom;
+}
+
+// This method returns the first CSSPropertyId of remaining properties,
+// i.e. low priority properties. No properties depend on low priority
+// properties. So we don't need to resolve such properties quickly.
+// All low priority properties are obtained by using
+// firstCSSPropertyId<LowPriorityProperties> and
+// lastCSSPropertyId<LowPriorityProperties>.
+template<>
+inline CSSPropertyID StylePropertyRange::firstCSSPropertyId<LowPriorityProperties>()
+{
+    static_assert(CSSPropertyAlignContent == CSSPropertyZoom + 1, "CSSPropertyAlignContent should be the first low priority property");
+    return CSSPropertyAlignContent;
+}
+
+// This method returns the last CSSPropertyId of low priority properties.
+template<>
+inline CSSPropertyID StylePropertyRange::lastCSSPropertyId<LowPriorityProperties>()
+{
+    return static_cast<CSSPropertyID>(lastCSSProperty);
+}
+
+} // namespace blink
+
+#endif // StylePropertyRange_h