Bug 773296 - Part 9: Give nsCSSScanner the ability to remember when it encounters a "var(" token. r=dbaron

This is the first part of handling variable references in regular
properties.  We have the scanner set a flag whenever it returns a "var("
token, so that when we come to the end of parsing a property that
failed, we know that it is because of a variable reference.

layout/style/nsCSSScanner.cpp

@@ -353,6 +353,7 @@ nsCSSScanner::nsCSSScanner(const nsAString& aBuffer, uint32_t aLineNumber)
   , mSVGMode(false)
   , mRecording(false)
   , mSeenBadToken(false)
+  , mSeenVariableReference(false)
 {
   MOZ_COUNT_CTOR(nsCSSScanner);
 }
@@ -721,6 +722,8 @@ nsCSSScanner::ScanIdent(nsCSSToken& aToken)
   aToken.mType = eCSSToken_Function;
   if (aToken.mIdent.LowerCaseEqualsLiteral("url")) {
     NextURL(aToken);
+  } else if (aToken.mIdent.LowerCaseEqualsLiteral("var")) {
+    mSeenVariableReference = true;
   }
   return true;
 }

layout/style/nsCSSScanner.h

@@ -178,13 +178,12 @@ class nsCSSScanner {
   }
 
   // Reset or check whether a BAD_URL or BAD_STRING token has been seen.
-  void ClearSeenBadToken() {
-    mSeenBadToken = false;
-  }
+  void ClearSeenBadToken() { mSeenBadToken = false; }
+  bool SeenBadToken() const { return mSeenBadToken; }
 
-  bool SeenBadToken() const {
-    return mSeenBadToken;
-  }
+  // Reset or check whether a "var(" FUNCTION token has been seen.
+  void ClearSeenVariableReference() { mSeenVariableReference = false; }
+  bool SeenVariableReference() const { return mSeenVariableReference; }
 
   // Get the 1-based line number of the last character of
   // the most recently processed token.
@@ -319,6 +318,7 @@ protected:
   bool mSVGMode;
   bool mRecording;
   bool mSeenBadToken;
+  bool mSeenVariableReference;
 };
 
 #endif /* nsCSSScanner_h___ */