Reland linux_aura: Implement most of DesktopScreenX11.

ui/views/widget/desktop_aura/desktop_screen_x11.h

Index: ui/views/widget/desktop_aura/desktop_screen_x11.h
diff --git a/ui/views/widget/desktop_aura/desktop_screen_x11.h b/ui/views/widget/desktop_aura/desktop_screen_x11.h
new file mode 100644
index 0000000000000000000000000000000000000000..1b9a8320a36244b8f6d6bd85881bbe39bd7f4c31
--- /dev/null
+++ b/ui/views/widget/desktop_aura/desktop_screen_x11.h
@@ -0,0 +1,95 @@
+// Copyright (c) 2013 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 UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_SCREEN_X11_H_
+#define UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_SCREEN_X11_H_
+
+#include "base/message_loop/message_pump_dispatcher.h"
+#include "base/observer_list.h"
+#include "base/timer/timer.h"
+#include "ui/gfx/screen.h"
+#include "ui/views/views_export.h"
+
+namespace gfx {
+class Display;
+}
+
+typedef unsigned long XID;
+typedef XID Window;
+typedef struct _XDisplay Display;
+
+namespace views {
+class DesktopScreenX11Test;
+
+// Our singleton screen implementation that talks to xrandr.
+class VIEWS_EXPORT DesktopScreenX11 : public gfx::Screen,
+                                      public base::MessagePumpDispatcher {
+ public:
+  DesktopScreenX11();
+
+  virtual ~DesktopScreenX11();
+
+  // Takes a set of displays and dispatches the screen change events to
+  // listeners. Exposed for testing.
+  void ProcessDisplayChange(const std::vector<gfx::Display>& displays);
+
+  // Overridden from gfx::Screen:
+  virtual bool IsDIPEnabled() OVERRIDE;
+  virtual gfx::Point GetCursorScreenPoint() OVERRIDE;
+  virtual gfx::NativeWindow GetWindowUnderCursor() OVERRIDE;
+  virtual gfx::NativeWindow GetWindowAtScreenPoint(const gfx::Point& point)
+      OVERRIDE;
+  virtual int GetNumDisplays() const OVERRIDE;
+  virtual std::vector<gfx::Display> GetAllDisplays() const OVERRIDE;
+  virtual gfx::Display GetDisplayNearestWindow(
+      gfx::NativeView window) const OVERRIDE;
+  virtual gfx::Display GetDisplayNearestPoint(
+      const gfx::Point& point) const OVERRIDE;
+  virtual gfx::Display GetDisplayMatching(
+      const gfx::Rect& match_rect) const OVERRIDE;
+  virtual gfx::Display GetPrimaryDisplay() const OVERRIDE;
+  virtual void AddObserver(gfx::DisplayObserver* observer) OVERRIDE;
+  virtual void RemoveObserver(gfx::DisplayObserver* observer) OVERRIDE;
+
+  // Overridden from MessagePumpDispatcher:
+  virtual bool Dispatch(const base::NativeEvent& event) OVERRIDE;
+
+ private:
+  friend class DesktopScreenX11Test;
+
+  // Constructor used in tests.
+  DesktopScreenX11(const std::vector<gfx::Display>& test_displays);
+
+  // Builds a list of displays from the current screen information offered by
+  // the X server.
+  std::vector<gfx::Display> BuildDisplaysFromXRandRInfo();
+
+  // We delay updating the display so we can coalesce events.
+  void ConfigureTimerFired();
+
+  Display* xdisplay_;
+  ::Window x_root_window_;
+
+  // Whether the x server supports the XRandR extension.
+  bool has_xrandr_;
+
+  // The base of the event numbers used to represent XRandr events used in
+  // decoding events regarding output add/remove.
+  int xrandr_event_base_;
+
+  // The display objects we present to chrome.
+  std::vector<gfx::Display> displays_;
+
+  // The timer to delay configuring outputs. See also the comments in
+  // Dispatch().
+  scoped_ptr<base::OneShotTimer<DesktopScreenX11> > configure_timer_;
+
+  ObserverList<gfx::DisplayObserver> observer_list_;
+
+  DISALLOW_COPY_AND_ASSIGN(DesktopScreenX11);
+};
+
+}  // namespace views
+
+#endif  // UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_SCREEN_X11_H_