Embedding a webgl-operate canvas inside a cross-origin (sandboxed) iframe leads to runtime TypeError

[bakoe]

Since integrating #270, embedding a webgl-operate based canvas inside a cross-origin iframe that is not explicitly trusted via sandbox="allow-top-navigation" leads to a runtime TypeError, independent of whether the GET parameters are actually set for masquerading or not.

View this CodeSandbox for a live example of the runtime error: https://codesandbox.io/s/sleepy-wood-wrxnl

SecurityError: Blocked a frame with origin "https://wrxnl.csb.app" from accessing a cross-origin frame. Protocols, domains, and ports must match.

Changing the webgl-operate version from 0.7.5 to 0.7.1 in the CodeSandbox makes the error disappear:

https://codesandbox.io/s/vigorous-mclaren-4s7p2

Thus, we should wrap the two window.top.location accesses introduced by #270 with corresponding try/catch blocks:

webgl-operate/source/auxiliaries.ts

Line 308 in 282d4c3

search = window.top.location.search;

webgl-operate/source/auxiliaries.ts

Lines 321 to 322 in 282d4c3

	// For iframe contents (i. e., the embedded /examples/ files), look within the top frame's search params
	match = window.top.location.search.match(re);