Introduce DisplayProvider for DisplayCompositor.

services/ui/surfaces/display_provider.h

+// 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.
+
+#ifndef SERVICES_UI_SURFACES_DISPLAY_PROVIDER_H_
+#define SERVICES_UI_SURFACES_DISPLAY_PROVIDER_H_
+
+#include <memory>
+
+#include "gpu/ipc/common/surface_handle.h"
+
+namespace cc {
+class BeginFrameSource;
+class Display;
+class FrameSinkId;
+}
+
+namespace ui {
+
+// Handles creating new cc::Displays and related classes for DisplayCompositor.
+class DisplayProvider {
+ public:
+  virtual ~DisplayProvider() {}
+
+  // Creates a new cc::Display for |surface_handle| with |frame_sink_id|. Will
+  // also create cc::BeginFrameSource and return it in |begin_frame_source|.
+  virtual std::unique_ptr<cc::Display> CreateDisplay(
+      const cc::FrameSinkId& frame_sink_id,
+      gpu::SurfaceHandle surface_handle,
+      std::unique_ptr<cc::BeginFrameSource>* begin_frame_source) = 0;
+};
+
+}  // namespace ui
+
+#endif  //  SERVICES_UI_SURFACES_DISPLAY_PROVIDER_H_