mojo: Create a basic clipboard.

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;
+  string data;

[sky, 2014/09/15 15:28:20]

Is there a reason you want a string here rather than an array? There has been
talk of forcing string types to be valid utf8.

+};
+
+interface Clipboard {
+  enum Type {
+    COPY_PASTE,
+    SELECTION,
+    DRAG
+  };
+
+  // Mime type constants
+  const string MIME_TYPE_TEXT = "text/plain";
+  const string MIME_TYPE_HTML = "text/html";
+  const string MIME_TYPE_URL = "text/url";
+
+  // Returns a sequence number which uniquely identifies clipboard state. This
+  // number is monotonically increasing, is increased when the clipboard state
+  // changes, and is provided by Windoes, Linux, and Mac.

[darin (slow to review), 2014/09/15 16:28:24]

nit: Windoes -> Windows

Perhaps there should be a comment here indicating how this may be used?

+  GetSequenceNumber(Type clipboard_type) => (uint64 sequence);
+
+  // Returns the available mime types. (Note: the chrome interface has a
+  // |contains_filenames| parameter here, but it appears to always be set
+  // to false.)
+  GetAvailableFormatMimeTypes(Type clipboard_types) => (string[] types);

[sky, 2014/09/15 15:28:20]

What does 'format' mean here? How about GetAvailableMimeTypes.

+
+  // Returns the data associated with a MIME type, returning NULL if that data
+  // doesn't exist. Note: because of the inherit raciness of clipboard access,
+  // 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) => (string? data);

[sky, 2014/09/15 15:28:20]

ReadMimeType (you use Mime above, not MIME).

+
+  // Writes a set of mime types to the clipboard. This will increment the
+  // sequence number.
+  WriteClipboardData(Type clipboard_type, MimeTypePair[] data);

[sky, 2014/09/15 15:28:20]

Is there ever a need to clear the clipboard? I'm specifically wondering if we
should allow data to be null?

+};
+
+}  // module mojo