Don't report an error when Map key type is not String.

editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/verifier/ErrorVerifier.java

Index: editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/verifier/ErrorVerifier.java
diff --git a/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/verifier/ErrorVerifier.java b/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/verifier/ErrorVerifier.java
index 4e2304137312d51d7a1d3fb43ec72de0fb9ae228..fe5ea4c1aa543404f78a87e1d7e657b438fdbde3 100644
--- a/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/verifier/ErrorVerifier.java
+++ b/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/verifier/ErrorVerifier.java
@@ -726,7 +726,6 @@ public class ErrorVerifier extends RecursiveASTVisitor<Void> {
     if (typeArguments != null) {
       NodeList<TypeName> arguments = typeArguments.getArguments();
       if (arguments.size() != 0) {
-        checkForInvalidTypeArgumentForKey(arguments);
         if (node.getConstKeyword() != null) {
           checkForInvalidTypeArgumentInConstTypedLiteral(
               arguments,
@@ -3305,24 +3304,6 @@ public class ErrorVerifier extends RecursiveASTVisitor<Void> {
   }
 
   /**
-   * Checks to ensure that first type argument to a map literal must be the 'String' type.
-   * 
-   * @param arguments a non-{@code null}, non-empty {@link TypeName} node list from the respective
-   *          {@link MapLiteral}
-   * @return {@code true} if and only if an error code is generated on the passed node
-   * @see CompileTimeErrorCode#INVALID_TYPE_ARGUMENT_FOR_KEY
-   */
-  private boolean checkForInvalidTypeArgumentForKey(NodeList<TypeName> arguments) {
-    TypeName firstArgument = arguments.get(0);
-    Type firstArgumentType = firstArgument.getType();
-    if (firstArgumentType != null && !firstArgumentType.equals(typeProvider.getStringType())) {
-      errorReporter.reportError(CompileTimeErrorCode.INVALID_TYPE_ARGUMENT_FOR_KEY, firstArgument);
-      return true;
-    }
-    return false;
-  }
-
-  /**
    * Checks to ensure that the passed {@link ListLiteral} or {@link MapLiteral} does not have a type
    * parameter as a type argument.
    *