[Chromedriver] Add Device Metrics override support to ChromeDriver via Capabilities

chrome/test/chromedriver/chrome/device_metrics.cc

Index: chrome/test/chromedriver/chrome/device_metrics.cc
diff --git a/chrome/test/chromedriver/chrome/device_metrics.cc b/chrome/test/chromedriver/chrome/device_metrics.cc
new file mode 100644
index 0000000000000000000000000000000000000000..72831e6833413fc65af414508bda82dfa061dd71
--- /dev/null
+++ b/chrome/test/chromedriver/chrome/device_metrics.cc
@@ -0,0 +1,16 @@
+// Copyright (c) 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 "chrome/test/chromedriver/chrome/device_metrics.h"
+
+DeviceMetrics::DeviceMetrics(int width, int height, double device_scale_factor)
+  : width(width),
+    height(height),
+    device_scale_factor(device_scale_factor),
+    emulate_viewport(false),
+    fit_window(true),
+    text_autosizing(true),
+    font_scale_factor(1) {}
+
+DeviceMetrics::~DeviceMetrics() {}