Implement Display id field in ScreenWin.

ui/gfx/screen_win.cc

Index: ui/gfx/screen_win.cc
diff --git a/ui/gfx/screen_win.cc b/ui/gfx/screen_win.cc
index 23dbc9d60fbb865a6124b32d57690bbb41d21ba2..3d0706ddf71c113f1fcc69efc98d679db9dd2314 100644
--- a/ui/gfx/screen_win.cc
+++ b/ui/gfx/screen_win.cc
@@ -6,24 +6,28 @@
 
 #include <windows.h>
 
+#include "base/hash.h"
 #include "base/logging.h"
+#include "base/strings/utf_string_conversions.h"
 #include "base/win/win_util.h"
 #include "ui/base/win/dpi.h"
 #include "ui/gfx/display.h"
 
 namespace {
 
-MONITORINFO GetMonitorInfoForMonitor(HMONITOR monitor) {
-  MONITORINFO monitor_info = { 0 };
+MONITORINFOEX GetMonitorInfoForMonitor(HMONITOR monitor) {
+  MONITORINFOEX monitor_info;
+  ZeroMemory(&monitor_info, sizeof(MONITORINFOEX));
   monitor_info.cbSize = sizeof(monitor_info);
   base::win::GetMonitorInfoWrapper(monitor, &monitor_info);
   return monitor_info;
 }
 
-gfx::Display GetDisplay(MONITORINFO& monitor_info) {
-  // TODO(oshima): Implement ID and Observer.
+gfx::Display GetDisplay(MONITORINFOEX& monitor_info) {
+  // TODO(oshima): Implement Observer.
+  int64 id = static_cast<int64>(base::Hash(WideToUTF8(monitor_info.szDevice)));
   gfx::Rect bounds = gfx::Rect(monitor_info.rcMonitor);
-  gfx::Display display(0, bounds);
+  gfx::Display display(id, bounds);
   display.set_work_area(gfx::Rect(monitor_info.rcWork));
   display.SetScaleAndBounds(ui::win::GetDeviceScaleFactor(), bounds);
   return display;
@@ -73,7 +77,7 @@ gfx::Display ScreenWin::GetDisplayNearestWindow(gfx::NativeView window) const {
     return GetPrimaryDisplay();
   }
 
-  MONITORINFO monitor_info;
+  MONITORINFOEX monitor_info;
   monitor_info.cbSize = sizeof(monitor_info);
   base::win::GetMonitorInfoWrapper(
       MonitorFromWindow(window_hwnd, MONITOR_DEFAULTTONEAREST), &monitor_info);
@@ -83,7 +87,8 @@ gfx::Display ScreenWin::GetDisplayNearestWindow(gfx::NativeView window) const {
 gfx::Display ScreenWin::GetDisplayNearestPoint(const gfx::Point& point) const {
   POINT initial_loc = { point.x(), point.y() };
   HMONITOR monitor = MonitorFromPoint(initial_loc, MONITOR_DEFAULTTONEAREST);
-  MONITORINFO mi = {0};
+  MONITORINFOEX mi;
+  ZeroMemory(&mi, sizeof(MONITORINFOEX));
   mi.cbSize = sizeof(mi);
   if (monitor && base::win::GetMonitorInfoWrapper(monitor, &mi)) {
     return GetDisplay(mi);
@@ -93,13 +98,13 @@ gfx::Display ScreenWin::GetDisplayNearestPoint(const gfx::Point& point) const {
 
 gfx::Display ScreenWin::GetDisplayMatching(const gfx::Rect& match_rect) const {
   RECT other_bounds_rect = match_rect.ToRECT();
-  MONITORINFO monitor_info = GetMonitorInfoForMonitor(MonitorFromRect(
+  MONITORINFOEX monitor_info = GetMonitorInfoForMonitor(MonitorFromRect(
       &other_bounds_rect, MONITOR_DEFAULTTONEAREST));
   return GetDisplay(monitor_info);
 }
 
 gfx::Display ScreenWin::GetPrimaryDisplay() const {
-  MONITORINFO mi = GetMonitorInfoForMonitor(
+  MONITORINFOEX mi = GetMonitorInfoForMonitor(
       MonitorFromWindow(NULL, MONITOR_DEFAULTTOPRIMARY));
   gfx::Display display = GetDisplay(mi);
   // TODO(kevers|girard): Test if these checks can be reintroduced for high-DIP