Add support for virtual displays

ui/display/chromeos/display_snapshot_virtual.cc

+// 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.
+
+#include "ui/display/chromeos/display_snapshot_virtual.h"
+
+#include <inttypes.h>
+
+#include "base/strings/stringprintf.h"
+#include "ui/display/types/display_mode.h"
+
+namespace ui {
+
+namespace {
+
+// For a non hi-DPI display (96 dpi) use a pitch of 265µm.
+static const float kVirtualDisplayPitchMM = 0.265;
+
+}  // namespace
+
+DisplaySnapshotVirtual::DisplaySnapshotVirtual(int64_t display_id,
+                                               const gfx::Size& display_size)
+    : DisplaySnapshot(display_id,
+                      gfx::Point(0, 0),
+                      // Calculate physical size assuming 96dpi display.
+                      gfx::Size(display_size.width() * kVirtualDisplayPitchMM,
+                                display_size.height() * kVirtualDisplayPitchMM),
+                      DISPLAY_CONNECTION_TYPE_VIRTUAL,
+                      false,
+                      false,
+                      "Virtual display",
+                      std::vector<const DisplayMode*>(),
+                      nullptr,
+                      nullptr) {
+  mode_.reset(new DisplayMode(display_size, false, 30));
+  modes_.push_back(mode_.get());
+
+  native_mode_ = modes_.front();
+}
+
+DisplaySnapshotVirtual::~DisplaySnapshotVirtual() {}
+
+std::string DisplaySnapshotVirtual::ToString() const {
+  return base::StringPrintf(
+      "Virtual id=%" PRId64 " current_mode=%s physical_size=%s", display_id_,
+      current_mode_ ? current_mode_->ToString().c_str() : "nullptr",
+      physical_size_.ToString().c_str());
+}
+
+}  // namespace ui