Change analyzer to not complain about string+string.

compiler/java/com/google/dart/compiler/resolver/TypeErrorCode.java

Index: compiler/java/com/google/dart/compiler/resolver/TypeErrorCode.java
diff --git a/compiler/java/com/google/dart/compiler/resolver/TypeErrorCode.java b/compiler/java/com/google/dart/compiler/resolver/TypeErrorCode.java
index 20c4aa699ea936a166fb8ec2e9a383908aa80a1d..c121dbe76ae32fbf940a63822e7a2b519dcdebc3 100644
--- a/compiler/java/com/google/dart/compiler/resolver/TypeErrorCode.java
+++ b/compiler/java/com/google/dart/compiler/resolver/TypeErrorCode.java
@@ -63,7 +63,6 @@ public enum TypeErrorCode implements ErrorCode {
   OPERATOR_INDEX_ASSIGN_VOID_RETURN_TYPE("operator '[]=' must have a return type of 'void'"),
   OPERATOR_WRONG_OPERAND_TYPE("operand of \"%s\" must be assignable to \"%s\", found \"%s\""),
   OVERRIDING_STATIC_MEMBER("overriding static member \"%s\" of \"%s\""),
-  PLUS_CANNOT_BE_USED_FOR_STRING_CONCAT("'%s' cannot be used for string concatentation, use string interpolation or a StringBuffer instead"),
   REDIRECTION_CONSTRUCTOR_TARGET_MUST_BE_SUBTYPE(
       "Target type of redirecting factory constructor '%s' is not subtype of '%s'"),
   SETTER_RETURN_TYPE("Specified return type of setter '%s' is non-void"),
@@ -128,4 +127,4 @@ public enum TypeErrorCode implements ErrorCode {
   public boolean needsRecompilation() {
     return this.needsRecompilation;
   }
-}
+}