chrome: Improve positioning of the "Find" widget (fixes #3461)

The "Find" widget will be excluded from regions near the edges of the window
that contain overlays, draggable regions or titlebar.

libcef/browser/geometry_util.h

@@ -0,0 +1,29 @@
+// Copyright (c) 2022 The Chromium Embedded Framework Authors. All rights
+// reserved. Use of this source code is governed by a BSD-style license that
+// can be found in the LICENSE file.
+
+#ifndef CEF_LIBCEF_BROWSER_GEOMETRY_UTIL_H_
+#define CEF_LIBCEF_BROWSER_GEOMETRY_UTIL_H_
+#pragma once
+
+namespace gfx {
+class Rect;
+}
+
+// Create a new rectangle from the input |rect| rectangle that is fully visible
+// on provided |screen_rect| screen. The width and height of the resulting
+// rectangle are clamped to the screen width and height respectively if they
+// would overflow.
+gfx::Rect MakeVisibleOnScreenRect(const gfx::Rect& rect,
+                                  const gfx::Rect& screen);
+
+// Possibly subtract |overlay| from |bounds|. We only want to subtract overlays
+// that are inside |bounds| and close to the edges, so |max_distance| is the
+// maximum allowed distance between |overlay| and |bounds| extents in order to
+// trigger the subtraction. Subtraction will occur from the closest edge. If
+// distances are otherwise equal then top will be preferred followed by left.
+gfx::Rect SubtractOverlayFromBoundingBox(const gfx::Rect& bounds,
+                                         const gfx::Rect& overlay,
+                                         int max_distance);
+
+#endif  // CEF_LIBCEF_BROWSER_GEOMETRY_UTIL_H_