how to expansion the clickable area of the extension icon in the chromium fork version 88?

I have a chromium fork of version 88, and i changed the size of extension icon from 28*28 to 68x68, but now i have met a problem, the clickable area was always appeared below the bottom half of the extension icon,and the size of hover area of the mouse was still 28x28.

Q: how can i make the whole area size of 68x68 being clickable ?

This is the code I modify:

file: chrome\browser\ui\layout_constants.cc:78

case TOOLBAR_BUTTON_HEIGHT:
     // return touch_ui ? 48 : 28;
     return touch_ui ? 48 : 68;```