Support argument definition test operator (issue 4264)

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

Index: compiler/javatests/com/google/dart/compiler/parser/SyntaxTest.java
===================================================================
--- compiler/javatests/com/google/dart/compiler/parser/SyntaxTest.java	(revision 11387)
+++ compiler/javatests/com/google/dart/compiler/parser/SyntaxTest.java	(working copy)
@@ -1223,6 +1223,29 @@
             ParserErrorCode.EXPECTED_TOKEN, 2, 15);
   }
 
+  public void test_abstractMethod_withModifier() {
+    parseUnit("test.dart", Joiner.on("\n").join(
+        "class C {",
+        "  abstract m(a, b, c);",
+        "}"));
+  }
+
+  public void test_abstractMethod_withoutModifier() {
+    parseUnit("test.dart", Joiner.on("\n").join(
+        "class C {",
+        "  m(a, b, c);",
+        "}"));
+  }
+
+  public void test_argumentDefinitionTest() {
+    parseUnit("test.dart", Joiner.on("\n").join(
+        "class C {",
+        "  m([p = 0]) {",
+        "    return ?p;",
+        "  }",
+        "}"));
+  }
+
   public void test_assignToNonAssignable() throws Exception {
     parseUnit("phony_assign_to_non_assignable.dart",
         Joiner.on("\n").join(