Revert of Remove unused PPB_View_Dev

ppapi/cpp/dev/view_dev.cc

+// Copyright (c) 2012 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 "ppapi/cpp/dev/view_dev.h"
+
+#include "ppapi/c/dev/ppb_view_dev.h"
+#include "ppapi/cpp/module_impl.h"
+
+namespace pp {
+
+namespace {
+
+template <> const char* interface_name<PPB_View_Dev>() {
+  return PPB_VIEW_DEV_INTERFACE;
+}
+
+}  // namespace
+
+float ViewDev::GetDeviceScale() const {
+  if (!has_interface<PPB_View_Dev>())
+    return 1.0f;
+  return get_interface<PPB_View_Dev>()->GetDeviceScale(pp_resource());
+}
+
+float ViewDev::GetCSSScale() const {
+  if (!has_interface<PPB_View_Dev>())
+    return 1.0f;
+  return get_interface<PPB_View_Dev>()->GetCSSScale(pp_resource());
+}
+
+}  // namespace pp