mojom: Add associative arrays to the mojom language.

mojo/public/tools/bindings/pylib/mojom_tests/parse/parser_unittest.py

Index: mojo/public/tools/bindings/pylib/mojom_tests/parse/parser_unittest.py
diff --git a/mojo/public/tools/bindings/pylib/mojom_tests/parse/parser_unittest.py b/mojo/public/tools/bindings/pylib/mojom_tests/parse/parser_unittest.py
index 2fa172fb60c8248ae26d1ac6b0ca27b5ec9583f3..abfb8779547ea87d4e653a1bdff507a419e06c57 100644
--- a/mojo/public/tools/bindings/pylib/mojom_tests/parse/parser_unittest.py
+++ b/mojo/public/tools/bindings/pylib/mojom_tests/parse/parser_unittest.py
@@ -672,16 +672,47 @@ class ParserTest(unittest.TestCase):
             r" *int32\[999999999999\] too_big_array;$"):
       parser.Parse(source2, "my_file.mojom")
 
-    source3 = """\
-        struct MyStruct {
-          int32[abcdefg] not_a_number;
-        };
-        """
-    with self.assertRaisesRegexp(
-        parser.ParseError,
-        r"^my_file\.mojom:2: Error: Unexpected 'abcdefg':\n"
-        r" *int32\[abcdefg\] not_a_number;"):
-      parser.Parse(source3, "my_file.mojom")
+  def testValidAssociativeArrays(self):
+    """Tests that we can parse valid associative array structures."""
+
+    source1 = "struct MyStruct { uint8[string] data; };"
+    expected1 = ast.Mojom(
+        None,
+        ast.ImportList(),
+        [ast.Struct(
+            'MyStruct',
+            None,
+            ast.StructBody(
+                [ast.StructField('data', None, 'uint8{string}', None)]))])
+    self.assertEquals(parser.Parse(source1, "my_file.mojom"), expected1)
+
+    source2 = "interface MyInterface { MyMethod(uint8[string] a); };"
+    expected2 = ast.Mojom(
+        None,
+        ast.ImportList(),
+        [ast.Interface(
+            'MyInterface',
+            None,
+            ast.InterfaceBody(
+                ast.Method(
+                    'MyMethod',
+                    None,
+                    ast.ParameterList(
+                      ast.Parameter('a', None, 'uint8{string}')),
+                    None)))])
+    self.assertEquals(parser.Parse(source2, "my_file.mojom"), expected2)
+
+    source3 = "struct MyStruct { uint8[string][] data; };"
+    expected3 = ast.Mojom(
+        None,
+        ast.ImportList(),
+        [ast.Struct(
+            'MyStruct',
+            None,
+            ast.StructBody(
+                [ast.StructField('data', None, 'uint8{string}[]', None)]))])
+    self.assertEquals(parser.Parse(source3, "my_file.mojom"), expected3)
+
 
   def testValidMethod(self):
     """Tests parsing method declarations."""