mojom: Add associative arrays to the mojom language.

mojo/services/public/interfaces/clipboard/clipboard.mojom

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 module mojo {
 
 // A wrapper type which is just a Key/Value pair. Workaround until we get
 // proper maps in mojom.
 struct MimeTypePair {
   string mime_type;
@@ skipping 29 matching lines @@
   // this may return NULL even if you just verified that it exists with
   // GetAvailableFormatMimeTypes(). We don't want to provide one API to return
   // the entire clipboard state because the combined size of the clipboard can
   // be megabytes, especially when image data is involved.
   ReadMimeType(Type clipboard_type, string mime_type) => (uint8[]? data);
 
   // Writes a set of mime types to the clipboard. This will increment the
   // sequence number. In the case of an empty or NULL list, this will just
   // clear the clipboard.
   WriteClipboardData(Type clipboard_type, MimeTypePair[]? data);
+
+  FakeTestMethod() => (string[string] mapping);

[yzshen1, 2014/09/27 00:01:58]

I think the constraint is that only primitive types and string are allowed to be
key, right? In the case of string, do you allow null as key? (I guess not.)

[Elliot Glaysher, 2014/10/02 19:54:03]

Correct. We verify that we don't pass "string?" at the grammar level. (And then
rely on Array<String> checking the nullness of the incoming strings during
validation.)

 };
 
 }  // module mojo