add voice interaction shortcut.

components/arc/common/voice_interaction.mojom

+// Copyright 2017 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.
+//
+// Next MinVersion: 1
+
+module arc.mojom;
+
+// Represents view structure to be passed to ARC. The view
+// structure is synthesized from the AXStructure, which
+// is a simplified representation of the DOM tree. We
+// map each node of the AXStructure into a view element.
+struct VoiceInteractionStructure {
+  // Whether this is a valid response
+  bool success;
+
+  // Geometry of the view in pixels
+  int32 x;
+  int32 y;
+  int32 width;
+  int32 height;
+
+  // Text of the view in utf-16 encoding
+  array<uint8> text;

[xiyuan, 2017/03/14 17:55:31]

Do we have to pass utf16 like this? It is not a good way to pass such data,
things such as endianess might cause tricky bugs.

Have we considered using mojo.common.mojom.String16 ?

https://cs.chromium.org/chromium/src/mojo/common/string16.mojom?rcl=bbd052efa...

[Muyuan, 2017/03/14 21:37:01]

String16 does not seem to be implemented in Java side (got codegen error) and my
experiment with string16 indicates that it's UTF-16 LE regardless of
architecture.

[xiyuan, 2017/03/15 15:58:15]

Acknowledged.

+
+  // Text properties
+  float text_size;
+  int32 color;
+  int32 bgcolor;
+  bool bold;
+  bool italic;
+  bool underline;
+  bool line_through;
+
+  // Is the text selected
+  bool has_selection;
+  // Start and end unicode character position of the selection, inclusive.
+  int32 start_selection;
+  int32 end_selection;
+
+  // Fake Android view class name of the element.  Each node is assigned
+  // a closest approximation of Android's views.
+  string class_name;
+
+  // Children of current node
+  array<VoiceInteractionStructure> children;
+};
+
+// Handles voice interaction queries from Android.
+// Next method ID: 2
+interface VoiceInteractionHost {
+  // Returns a screenshot of current focused window or empty bytes if
+  // no window is focused.
+  CaptureFocusedWindow@0() => (array<uint8> png_data);
+
+  // Returns view hierarchy of current window represented as
+  // VoiceInteractionStructure.
+  GetVoiceInteractionStructure@1() => (VoiceInteractionStructure structure);
+};
+
+// Connects with Android system server.
+// Next method ID:2
+interface VoiceInteractionCaptureInstance {
+  Init@0(VoiceInteractionHost host_ptr);
+
+  // Starts the voice interaction session in container.
+  StartVoiceInteractionSession@1();
+};
+
+// Connects with ArcHome.
+// Next method ID: 1
+interface VoiceInteractionArcHomeInstance {
+  Init@0(VoiceInteractionHost host_ptr);
+};