Add support for a virtual display on ChromeOS

ui/display/chromeos/display_snapshot_virtual.h

Index: ui/display/chromeos/display_snapshot_virtual.h
diff --git a/ui/display/chromeos/display_snapshot_virtual.h b/ui/display/chromeos/display_snapshot_virtual.h
new file mode 100644
index 0000000000000000000000000000000000000000..1b6d5d693aafeba5d1178f2453070042d4a00fd4
--- /dev/null
+++ b/ui/display/chromeos/display_snapshot_virtual.h
@@ -0,0 +1,25 @@
+// 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.
+
+#ifndef UI_DISPLAY_TYPES_DISPLAY_SNAPSHOT_VIRTUAL_H_
+#define UI_DISPLAY_TYPES_DISPLAY_SNAPSHOT_VIRTUAL_H_
+
+#include "ui/display/types/display_snapshot.h"
+
+namespace ui {
+
+class DisplaySnapshotVirtual : public DisplaySnapshot {

[Daniel Erat, 2015/02/23 23:14:54]

add a comment documenting what this class is for

[robert.bradford, 2015/03/03 19:58:00]

Done.

+ public:
+  DisplaySnapshotVirtual(uint32_t index, DisplayMode* mode);

[Daniel Erat, 2015/02/23 23:14:54]

add a comment documenting what |index| is and whether ownership of |mode| is
passed (and if it is, used scoped_ptr instead)

[robert.bradford, 2015/03/03 19:58:00]

The constructor prototype now looks like this:

DisplaySnapshotVirtual(int64_t display_id, gfx::Size display_size);

+  ~DisplaySnapshotVirtual() override;
+
+  // DisplaySnapshot overrides.
+  std::string ToString() const override;
+

[oshima, 2015/02/24 19:43:21]

private:

[robert.bradford, 2015/03/03 19:58:00]

Done.

+  DISALLOW_COPY_AND_ASSIGN(DisplaySnapshotVirtual);
+};
+
+}  // namespace ui
+
+#endif  // UI_DISPLAY_TYPES_DISPLAY_SNAPSHOT_VIRTUAL_H_