MacViews: Implement SetCursor

ui/views/cocoa/views_nswindow_delegate.mm

Index: ui/views/cocoa/views_nswindow_delegate.mm
diff --git a/ui/views/cocoa/views_nswindow_delegate.mm b/ui/views/cocoa/views_nswindow_delegate.mm
index 7acae1ef479c81160d866e078438c18186794106..38a56c1a17bbe06df96b2812bc90982a9458a2b8 100644
--- a/ui/views/cocoa/views_nswindow_delegate.mm
+++ b/ui/views/cocoa/views_nswindow_delegate.mm
@@ -23,6 +23,18 @@
   return parent_->native_widget_mac();
 }
 
+- (NSCursor*)cursor {
+  return cursor_.get();
+}
+
+- (void)setCursor:(NSCursor*)newCursor {
+  if (cursor_.get() == newCursor)
+    return;
+
+  cursor_.reset([newCursor retain]);
+  [parent_->ns_window() resetCursorRects];
+}
+
 - (void)onWindowOrderWillChange:(NSWindowOrderingMode)orderingMode {
   parent_->OnVisibilityChangedTo(orderingMode != NSWindowOut);
 }