fix: Revert "feat: Corner Smoothing CSS rule" (#46231)

Revert "feat: Corner Smoothing CSS rule (#45185)"

This reverts commit b75e802280.

shell/renderer/electron_smooth_round_rect.h

@@ -1,36 +0,0 @@
-// Copyright (c) 2024 Salesforce, Inc.
-// Use of this source code is governed by the MIT license that can be
-// found in the LICENSE file.
-
-#ifndef ELECTRON_SHELL_RENDERER_API_ELECTRON_SMOOTH_ROUND_RECT_H_
-#define ELECTRON_SHELL_RENDERER_API_ELECTRON_SMOOTH_ROUND_RECT_H_
-
-#include "third_party/skia/include/core/SkPath.h"
-
-namespace electron {
-
-// Draws a rectangle that has smooth round corners for a given "smoothness"
-// value between 0.0 and 1.0 (representing 0% to 100%).
-//
-// The smoothness value determines how much edge length can be consumed by each
-// corner, scaling with respect to that corner's radius. The smoothness will
-// dynamically scale back if there is not enough edge length, similar to how
-// the corner radius backs off when there isn't enough edge length.
-//
-// Each corner's radius can be supplied independently. Corner radii are expected
-// to already be balanced (Radius1 + Radius2 <= Length, for each given side).
-//
-// Elliptical corner radii are not currently supported.
-SkPath DrawSmoothRoundRect(float x,
-                           float y,
-                           float width,
-                           float height,
-                           float smoothness,
-                           float top_left_radius,
-                           float top_right_radius,
-                           float bottom_right_radius,
-                           float bottom_left_radius);
-
-}  // namespace electron
-
-#endif  // ELECTRON_SHELL_RENDERER_API_ELECTRON_SMOOTH_ROUND_RECT_H_