color: Read all displays' color profiles on Windows

ui/display/win/color_profile_reader.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 UI_DISPLAY_WIN_COLOR_PROFILE_READER_H_
+#define UI_DISPLAY_WIN_COLOR_PROFILE_READER_H_
+
+#include "base/callback.h"
+#include "base/memory/weak_ptr.h"
+#include "base/strings/string16.h"
+#include "ui/display/display_export.h"
+#include "ui/gfx/color_space.h"
+
+#include <map>
+#include <string>
+
+namespace display {
+namespace win {
+
+// Monitor ICC profiles are stored in the filesystem, and a blocking read from
+// file is required to read them. This is expensive and shouldn't be done on the
+// main thread, so this class manages asynchronously doing these readings and
+// calling back into its client when the profiles are noticed to have changed.
+class DISPLAY_EXPORT ColorProfileReader {
+ public:
+  class Client {
+   public:
+    virtual void OnColorProfilesChanged() = 0;
+  };
+
+  ColorProfileReader(Client* client);
+  ~ColorProfileReader();
+
+  // Check to see if the screen profile filenames have changed. If so, spawn a
+  // task to update them. When the task has completed, this will call the
+  // client's OnColorProfileReaderChanged on the main thread.
+  void UpdateIfNeeded();
+
+  // Look up the color space for a given device name. If the device's color
+  // profile has not yet been read, this will return sRGB (which is what the
+  // file on disk will say most of the time).
+  const gfx::ColorSpace& GetDisplayColorSpace(int64_t id) const;
+
+ private:
+  typedef std::map<base::string16, base::string16> DeviceToPathMap;
+  typedef std::map<base::string16, std::string> DeviceToDataMap;
+
+  // Enumerate displays and return a map to their ICC profile path.
+  static DeviceToPathMap BuildDeviceToPathMap();
+
+  // Do the actual reading from the filesystem. This needs to be run off of the
+  // main thread.
+  static DeviceToDataMap ReadProfilesOnBackgroundThread(
+      DeviceToPathMap new_device_to_path_map);
+
+  // Called on the main thread when the read has completed.
+  void ReadProfilesCompleted(DeviceToDataMap device_to_data_map);
+
+  Client* const client_ = nullptr;
+  bool update_in_flight_ = false;
+  DeviceToPathMap device_to_path_map_;
+  std::map<int64_t, gfx::ColorSpace> display_id_to_color_space_map_;
+  const gfx::ColorSpace default_color_space_ = gfx::ColorSpace::CreateSRGB();
+  base::WeakPtrFactory<ColorProfileReader> weak_factory_;
+};
+
+}  // namespace win
+}  // namespace display
+
+#endif  // UI_DISPLAY_WIN_COLOR_PROFILE_READER_H_