Use begin/end istead of first/last for rule ranges.

Source/core/css/resolver/MatchResult.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 46 matching lines @@
 
 WTF_ALLOW_MOVE_AND_INIT_WITH_MEM_FUNCTIONS(blink::MatchedProperties);
 
 namespace blink {
 
 class MatchResult {
     STACK_ALLOCATED();
 public:
     void addMatchedProperties(const StylePropertySet* properties, unsigned linkMatchType = CSSSelector::MatchAll, PropertyWhitelistType = PropertyWhitelistNone);
 
-    int firstRule() const { return 0; }
-    int lastRule() const { return matchedProperties.size() - 1; }
-    int firstUARule() const { return lastUARuleIndex == -1 ? -1 : 0; }
-    int lastUARule() const { return lastUARuleIndex; }
-    int firstAuthorRule() const { return lastUARuleIndex + 1; }
-    int lastAuthorRule() const { return lastRule(); }
+    unsigned begin() const { return 0; }
+    unsigned end() const { return matchedProperties.size(); }
+    unsigned beginUA() const { return 0; }
+    unsigned endUA() const { return uaEnd; }
+    unsigned beginAuthor() const { return uaEnd; }
+    unsigned endAuthor() const { return matchedProperties.size(); }
 
     WillBeHeapVector<MatchedProperties, 64> matchedProperties;
-    int lastUARuleIndex = -1;
+    unsigned uaEnd = 0;
     bool isCacheable = true;
 };
 
 inline bool operator==(const MatchedProperties& a, const MatchedProperties& b)
 {
     return a.properties == b.properties && a.m_types.linkMatchType == b.m_types.linkMatchType;
 }
 
 inline bool operator!=(const MatchedProperties& a, const MatchedProperties& b)
 {
     return !(a == b);
 }
 
 } // namespace blink
 
 #endif // MatchResult_h