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diff --git a/chromeos/monitor/output_configurator.h b/chromeos/monitor/output_configurator.h
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+// 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.
+
+#ifndef CHROMEOS_MONITOR_OUTPUT_CONFIGURATOR_H_
+#define CHROMEOS_MONITOR_OUTPUT_CONFIGURATOR_H_
+#pragma once
+
+#include <X11/Xlib.h>
+#include <X11/extensions/dpms.h>
+#include <X11/extensions/Xrandr.h>
+
+// Xlib defines Status as int which causes our include of dbus/bus.h to fail
+// when it tries to name an enum Status.  Thus, we need to undefine it (note
+// that this will cause a problem if code needs to use the Status type).
+// RootWindow causes similar problems in that there is a Chromium type with that
+// name.
+#undef Status
+#undef RootWindow
+
+#include "base/basictypes.h"
+#include "base/event_types.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/message_loop.h"
+#include "chromeos/chromeos_export.h"
+
+namespace chromeos {
+
+// The information we need to cache from an output to implement operations such
+// as power state but also to eliminate duplicate operations within a given
+// action (determining which CRTC to use for a given output, for example).
+struct CachedOutputDescription {
+  RROutput output;
+  RRCrtc crtc;
+  RRMode mirror_mode;
+  RRMode ideal_mode;
+  int x;
+  int y;
+  bool is_connected;
+  bool is_powered_on;
+  bool is_internal;
+};
+
+// Used to describe the state of a multi-monitor configuration.
+enum State {
+  STATE_INVALID,
+  STATE_HEADLESS,
+  STATE_SINGLE,
+  STATE_DUAL_MIRROR,
+  STATE_DUAL_PRIMARY_ONLY,
+  STATE_DUAL_SECONDARY_ONLY,
+};
+
+// This class interacts directly with the underlying Xrandr API to manipulate
+// CTRCs and Outputs.  It will likely grow more state, over time, or expose
+// Output info in other ways as more of the Chrome display code grows up around
+// it.
+class CHROMEOS_EXPORT OutputConfigurator : public MessageLoop::Dispatcher {
+ public:
+  OutputConfigurator();
+  virtual ~OutputConfigurator();
+
+  // Called when the user hits ctrl-F4 to request a display mode change.
+  // This method should only return false if it was called in a single-head or
+  // headless mode.
+  bool CycleDisplayMode();
+
+  // Called when powerd notifies us that some set of displays should be turned
+  // on or off.  This requires enabling or disabling the CRTC associated with
+  // the display(s) in question so that the low power state is engaged.
+  bool ScreenPowerSet(bool power_on, bool all_displays);
+
+  // Called when an RRNotify event is received.  The implementation is
+  // interested in the cases of RRNotify events which correspond to output
+  // add/remove events.  Note that Output add/remove events are sent in response
+  // to our own reconfiguration operations so spurious events are common.
+  // Spurious events will have no effect.
+  virtual bool Dispatch(const base::NativeEvent& event) OVERRIDE;
+
+ private:
+  // Updates |output_count_|, |output_cache_|, |mirror_supported_|,
+  // |primary_output_index_|, and |secondary_output_index_| with new data.
+  // Returns true if the update succeeded or false if it was skipped since no
+  // actual change was observed.
+  // Note that |output_state_| is not updated by this call.
+  bool TryRecacheOutputs(Display* display, XRRScreenResources* screen);
+
+  // Uses the data stored in |output_cache_| and the given |new_state| to
+  // configure the Xrandr interface and then updates |output_state_| to reflect
+  // the new state.
+  void UpdateCacheAndXrandrToState(Display* display,
+                                   XRRScreenResources* screen,
+                                   Window window,
+                                   State new_state);
+
+  // A helper to re-cache instance variable state and transition into the
+  // appropriate default state for the observed displays.
+  bool RecacheAndUseDefaultState();
+
+  // Checks the |primary_output_index_|, |secondary_output_index_|, and
+  // |mirror_supported_| to see how many displays are currently connected and
+  // returns the state which is most appropriate as a default state for those
+  // displays.
+  State GetDefaultState() const;
+
+  // This is detected by the constructor to determine whether or not we should
+  // be enabled.  If we aren't running on ChromeOS, we can't assume that the
+  // Xrandr X11 extension is supported.
+  // If this flag is set to false, any attempts to change the output
+  // configuration to immediately fail without changing the state.
+  bool is_running_on_chrome_os_;
+
+  // The number of outputs in the output_cache_ array.
+  int output_count_;
+
+  // The list of cached output descriptions (|output_count_| elements long).
+  scoped_array<CachedOutputDescription> output_cache_;
+
+  // True if |output_cache_| describes a permutation of outputs which support a
+  // mirrored device mode.
+  bool mirror_supported_;
+
+  // The index of the primary connected output in |output_cache_|.  -1 if there
+  // is no primary output.  This implies the machine currently has no outputs.
+  int primary_output_index_;
+
+  // The index of the secondary connected output in |output_cache_|.  -1 if
+  // there is no secondary output.  This implies the machine currently has one
+  // output.
+  int secondary_output_index_;
+
+  // 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 state as derived from the outputs observed in |output_cache_|.
+  // This is used for rotating display modes.
+  State output_state_;
+
+  DISALLOW_COPY_AND_ASSIGN(OutputConfigurator);
+};
+
+}  // namespace chromeos
+
+#endif  // CHROMEOS_MONITOR_OUTPUT_CONFIGURATOR_H_