Add an error for obsolete raw strings (issue 4815)

compiler/javatests/com/google/dart/compiler/parser/NegativeParserTest.java

Index: compiler/javatests/com/google/dart/compiler/parser/NegativeParserTest.java
===================================================================
--- compiler/javatests/com/google/dart/compiler/parser/NegativeParserTest.java	(revision 13746)
+++ compiler/javatests/com/google/dart/compiler/parser/NegativeParserTest.java	(working copy)
@@ -355,6 +355,12 @@
         errEx(ParserErrorCode.DEPRECATED_USE_OF_FACTORY_KEYWORD, 1, 15, 7));
   }
 
+  public void test_deprecatedRawString() {
+    parseExpectWarnings(

[danrubel, 2012/10/17 21:55:35]

Perhaps it should be an error rather than a warning?
We want to forcefully suggest folks move to the new syntax.
Plus there is an *easy* cleanup wizard :-)

[danrubel, 2012/10/17 21:57:17]

Sorry. It is an error. The "parseExpectWarning" threw me off.

+        "String s() { return @'s'; }",
+        errEx(ParserErrorCode.DEPRECATED_RAW_STRING, 1, 21, 1));
+  }
+
   public void test_useExtendsInTypedef() {
     parseExpectErrors(Joiner.on("\n").join(
         "// filler filler filler filler filler filler filler filler filler filler",