Refactor screen/monitor so that gfx::Screen returns monitor object.

ash/tooltips/tooltip_controller.cc

Index: ash/tooltips/tooltip_controller.cc
diff --git a/ash/tooltips/tooltip_controller.cc b/ash/tooltips/tooltip_controller.cc
index 341128d2c12cbb6747fcdb27ffda27a9881cacfb..c1aaa0fd212d99236ad8dc8628ec75704c4c103d 100644
--- a/ash/tooltips/tooltip_controller.cc
+++ b/ash/tooltips/tooltip_controller.cc
@@ -65,7 +65,7 @@ int GetMaxWidth(int x, int y) {
   // TODO(varunjain): implementation duplicated in tooltip_manager_aura. Figure
   // out a way to merge.
   gfx::Rect monitor_bounds =
-      gfx::Screen::GetMonitorAreaNearestPoint(gfx::Point(x, y));
+      gfx::Screen::GetMonitorNearestPoint(gfx::Point(x, y)).bounds();
   return (monitor_bounds.width() + 1) / 2;
 }
 
@@ -155,7 +155,7 @@ class TooltipController::Tooltip {
 
     tooltip_rect.Offset(kCursorOffsetX, kCursorOffsetY);
     gfx::Rect monitor_bounds =
-        gfx::Screen::GetMonitorAreaNearestPoint(tooltip_rect.origin());
+        gfx::Screen::GetMonitorNearestPoint(tooltip_rect.origin()).bounds();
 
     // If tooltip is out of bounds on the x axis, we simply shift it
     // horizontally by the offset.