Implement a runtime headless mode for Linux

headless/lib/browser/headless_window_tree_host.h

Index: headless/lib/browser/headless_window_tree_host.h
diff --git a/headless/lib/browser/headless_window_tree_host.h b/headless/lib/browser/headless_window_tree_host.h
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index 0000000000000000000000000000000000000000..0ddbc910432915f3f2830e0112c4a64f2b4e2444
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+++ b/headless/lib/browser/headless_window_tree_host.h
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+// Copyright 2016 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 HEADLESS_LIB_BROWSER_HEADLESS_WINDOW_TREE_HOST_H_
+#define HEADLESS_LIB_BROWSER_HEADLESS_WINDOW_TREE_HOST_H_
+
+#include <stdint.h>
+
+#include <memory>
+
+#include "base/macros.h"
+#include "ui/aura/aura_export.h"
+#include "ui/aura/window_tree_host.h"
+#include "ui/events/platform/platform_event_dispatcher.h"
+#include "ui/gfx/geometry/insets.h"
+#include "ui/gfx/geometry/rect.h"
+
+namespace headless {
+
+class HeadlessWindowTreeHost : public aura::WindowTreeHost,
+                               public ui::PlatformEventDispatcher {
+ public:
+  explicit HeadlessWindowTreeHost(const gfx::Rect& bounds);
+  ~HeadlessWindowTreeHost() override;
+
+  // ui::PlatformEventDispatcher:
+  bool CanDispatchEvent(const ui::PlatformEvent& event) override;
+  uint32_t DispatchEvent(const ui::PlatformEvent& event) override;
+
+  // WindowTreeHost:
+  ui::EventSource* GetEventSource() override;
+  gfx::AcceleratedWidget GetAcceleratedWidget() override;
+  void ShowImpl() override;
+  void HideImpl() override;
+  gfx::Rect GetBounds() const override;
+  void SetBounds(const gfx::Rect& bounds) override;
+  gfx::Point GetLocationOnNativeScreen() const override;
+  void SetCapture() override;
+  void ReleaseCapture() override;
+  void SetCursorNative(gfx::NativeCursor cursor_type) override;
+  void MoveCursorToNative(const gfx::Point& location) override;
+  void OnCursorVisibilityChangedNative(bool show) override;
+  gfx::ICCProfile GetICCProfileForCurrentDisplay() override;
+
+ private:
+  gfx::Rect bounds_;
+
+  DISALLOW_COPY_AND_ASSIGN(HeadlessWindowTreeHost);
+};
+
+}  // namespace headless
+
+#endif  // HEADLESS_LIB_BROWSER_HEADLESS_WINDOW_TREE_HOST_H_