Add IsInternal property to gfx::Display

ui/gfx/display.cc

Index: ui/gfx/display.cc
diff --git a/ui/gfx/display.cc b/ui/gfx/display.cc
index 40608a1d21127d265463131cb069199d6015942b..10c4e850f78c885fbf70d98ac7f585aa64484fbc 100644
--- a/ui/gfx/display.cc
+++ b/ui/gfx/display.cc
@@ -35,6 +35,7 @@ float GetForcedDeviceScaleFactorImpl() {
 } // namespace
 
 const int64 Display::kInvalidDisplayID = -1;
+int64 Display::internal_display_id_ = Display::kInvalidDisplayID;
 
 // static
 float Display::GetForcedDeviceScaleFactor() {
@@ -129,11 +130,25 @@ gfx::Size Display::GetSizeInPixel() const {
 }
 
 std::string Display::ToString() const {
-  return base::StringPrintf("Display[%lld] bounds=%s, workarea=%s, scale=%f",
-                            static_cast<long long int>(id_),
-                            bounds_.ToString().c_str(),
-                            work_area_.ToString().c_str(),
-                            device_scale_factor_);
+  return base::StringPrintf(
+      "Display[%lld] bounds=%s, workarea=%s, scale=%f, %s",
+      static_cast<long long int>(id_),
+      bounds_.ToString().c_str(),
+      work_area_.ToString().c_str(),
+      device_scale_factor_,
+      is_internal() ? "internal" : "external");
+}
+
+bool Display::is_internal() const {
+  return is_valid() && (id_ == internal_display_id_);
+}
+
+int64 Display::internal_display_id() {
+  return internal_display_id_;
+}
+
+void Display::set_internal_display_id(int64 internal_display_id) {
+  internal_display_id_ = internal_display_id;
 }
 
 }  // namespace gfx