Ensure that zoom in/out works in Chrome OS mode on Windows 7+.

Fix is to send the special keystates over in the mouse wheel IPC message.

BUG=410792

Review URL: https://codereview.chromium.org/543203002

Cr-Commit-Position: refs/heads/master@{#293607}

win8/metro_driver/chrome_app_view_ash.cc

@@ -1160,7 +1160,7 @@ HRESULT ChromeAppViewAsh::OnWheel(
     return hr;
   DCHECK(pointer.IsMouse());
   SendMouseButton(pointer.x(), pointer.y(), pointer.wheel_delta(),
-                  ui::ET_MOUSEWHEEL, ui::EF_NONE, ui::EF_NONE,
+                  ui::ET_MOUSEWHEEL, GetKeyboardEventFlags(), ui::EF_NONE,
                   pointer.is_horizontal_wheel());
   return S_OK;
 }