Listen to Display reconfiguration and notify DisplayObservers on Mac.

ui/gfx/display_change_notifier.cc

Index: ui/gfx/display_change_notifier.cc
diff --git a/ui/gfx/display_change_notifier.cc b/ui/gfx/display_change_notifier.cc
new file mode 100644
index 0000000000000000000000000000000000000000..2fa73cf383f90b650cdc256ac378a109931cc0c1
--- /dev/null
+++ b/ui/gfx/display_change_notifier.cc
@@ -0,0 +1,81 @@
+// Copyright 2014 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.
+
+#include "ui/gfx/display_change_notifier.h"
+
+#include "ui/gfx/display.h"
+
+DisplayChangeNotifier::DisplayChangeNotifier() {
+}
+
+DisplayChangeNotifier::~DisplayChangeNotifier() {
+}
+
+void DisplayChangeNotifier::AddObserver(gfx::DisplayObserver* obs) {
+  observer_list_.AddObserver(obs);
+}
+
+void DisplayChangeNotifier::RemoveObserver(gfx::DisplayObserver* obs) {
+  observer_list_.RemoveObserver(obs);
+}
+
+void DisplayChangeNotifier::NotifyDisplaysChanged(
+    const std::vector<gfx::Display>& old_displays,
+    const std::vector<gfx::Display>& new_displays) {
+  typedef std::vector<gfx::Display>::const_iterator DisplayIt;
+  std::vector<gfx::Display>::const_iterator old_it = old_displays.begin();
+  for (; old_it != old_displays.end(); ++old_it) {
+    bool found = false;
+    for (std::vector<gfx::Display>::const_iterator new_it =
+         new_displays.begin(); new_it != new_displays.end(); ++new_it) {
+      if (old_it->id() == new_it->id()) {
+        found = true;
+        break;
+      }
+    }
+
+    if (!found) {
+      FOR_EACH_OBSERVER(gfx::DisplayObserver, observer_list_,
+                        OnDisplayRemoved(*old_it));
+    }
+  }
+
+  for (std::vector<gfx::Display>::const_iterator new_it =
+          new_displays.begin(); new_it != new_displays.end(); ++new_it) {
+    bool found = false;
+    for (std::vector<gfx::Display>::const_iterator old_it =
+         old_displays.begin(); old_it != old_displays.end(); ++old_it) {
+      if (new_it->id() != old_it->id())
+        continue;
+
+      uint32_t metrics = gfx::DisplayObserver::DISPLAY_METRIC_NONE;
+
+      if (new_it->bounds() != old_it->bounds())
+        metrics |= gfx::DisplayObserver::DISPLAY_METRIC_BOUNDS;
+
+      if (new_it->rotation() != old_it->rotation())
+        metrics |= gfx::DisplayObserver::DISPLAY_METRIC_ROTATION;
+
+      if (new_it->work_area() != old_it->work_area())
+        metrics |= gfx::DisplayObserver::DISPLAY_METRIC_WORK_AREA;
+
+      if (new_it->device_scale_factor() != old_it->device_scale_factor())
+        metrics |= gfx::DisplayObserver::DISPLAY_METRIC_DEVICE_SCALE_FACTOR;
+
+      if (metrics != gfx::DisplayObserver::DISPLAY_METRIC_NONE) {
+        FOR_EACH_OBSERVER(gfx::DisplayObserver,
+                          observer_list_,
+                          OnDisplayMetricsChanged(*new_it, metrics));
+      }
+
+      found = true;
+      break;
+    }
+
+    if (!found) {
+      FOR_EACH_OBSERVER(gfx::DisplayObserver, observer_list_,
+                        OnDisplayAdded(*new_it));
+    }
+  }
+}