fix(ios): navigation delegate class name conflict, closes #817

[pewsheen]

What kind of change does this PR introduce?

• Bugfix
• Feature
• Docs
• New Binding issue #___
• Code style update
• Refactor
• Build-related changes
• Other, please describe:

Does this PR introduce a breaking change?

• Yes, and the changes were approved in issue #___
• No

Checklist

• When resolving issues, they are referenced in the PR's title (e.g fix: remove a typo, closes #___, #___)
• A change file is added if any packages will require a version bump due to this PR per the instructions in the readme.
• I have added a convincing reason for adding this feature, if necessary

Other information

issue #817

Class name UIViewController was used in iOS's UIKit thus ClassDecl will fail and return None.

wry/src/webview/wkwebview/mod.rs

Lines 471 to 492 in ca7c8e4

	let navigation_delegate_cls = match ClassDecl::new("UIViewController", class!(NSObject)) {
	Some(mut cls) => {
	cls.add_ivar::<*mut c_void>("pending_scripts");
	cls.add_ivar::<*mut c_void>("navigation_policy_function");
	cls.add_ivar::<*mut c_void>("HasDownloadHandler");
	cls.add_method(
	sel!(webView:decidePolicyForNavigationAction:decisionHandler:),
	navigation_policy as extern "C" fn(&Object, Sel, id, id, id),
	);
	cls.add_method(
	sel!(webView:decidePolicyForNavigationResponse:decisionHandler:),
	navigation_policy_response as extern "C" fn(&Object, Sel, id, id, id),
	);
	cls.add_method(
	sel!(webView:didCommitNavigation:),
	did_commit_navigation as extern "C" fn(&Object, Sel, id, id),
	);
	add_download_methods(&mut cls);
	cls.register()
	}
	None => class!(UIViewController),
	};

Later set_ivar with pending_scripts to UIKit's UIViewController will panic because there is no ivar pending_scripts in it.

wry/src/webview/wkwebview/mod.rs

Lines 496 to 498 in ca7c8e4

	(*navigation_policy_handler).set_ivar(
	"pending_scripts",
	Box::into_raw(Box::new(pending_scripts.clone())) as *mut c_void,