[iOS] Presenting a modal sheet on top of a WKWebView causes it to lose focused, active state

• Component: WebKit2
• Status: RESOLVED FIXED

When a view controller is presented modally on top of a WKWebView, the web view is removed from the view hierarchy. This causes it to resign first responder status, and to signal the DOM that it is no longer in an active, focused window. In particular, this will cause any focused input element to lose focus. The result is that, for example, when focusing a credit card number field on a webpage and using Safari to capture credit card information from the camera, which involves a modal sheet, the field is no longer focused after dismissing the sheet.

Created attachment 248658 [details]
Add -[WKWebView _retainActiveFocusedState]

[Anders Carlsson]

Comment on attachment 248658 [details]
Add -[WKWebView _retainActiveFocusedState]

View in context: https://bugs.webkit.org/attachment.cgi?id=248658&action=review

> Source/WebKit2/UIProcess/API/Cocoa/WKWebView.mm:1779
> +- (void (^)(void))_retainActiveFocusedState

I really think we need a name here that indicates that this returns a block. I can't think of a name though :(

Fixed in <http://trac.webkit.org/r181511>.

[David Kilzer (:ddkilzer)]

(In reply to comment #3)
> Fixed in <http://trac.webkit.org/r181511>.

Many (most?) iOS layout tests crash here with a NULL deref after this change:

Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0   com.apple.WebKit              	0x0000000106c22231 WebKit::PageClientImpl::isViewWindowActive() + 37
1   com.apple.WebKit              	0x0000000106c2224f WebKit::PageClientImpl::isViewFocused() + 15
2   com.apple.WebKit              	0x0000000106d3128e WebKit::WebPageProxy::updateViewState(unsigned int) + 38
3   com.apple.WebKit              	0x0000000106d30909 WebKit::WebPageProxy::WebPageProxy(WebKit::PageClient&, WebKit::WebProcessProxy&, unsigned long long, WebKit::WebPageConfiguration const&) + 2195
4   com.apple.WebKit              	0x0000000106d3004b WebKit::WebPageProxy::create(WebKit::PageClient&, WebKit::WebProcessProxy&, unsigned long long, WebKit::WebPageConfiguration const&) + 69
5   com.apple.WebKit              	0x0000000106d929cb WebKit::WebProcessProxy::createWebPage(WebKit::PageClient&, WebKit::WebPageConfiguration const&) + 55
6   com.apple.WebKit              	0x0000000106d888fb WebKit::WebProcessPool::createWebPage(WebKit::PageClient&, WebKit::WebPageConfiguration) + 239
7   com.apple.WebKit              	0x0000000106dc2a6d -[WKContentView _commonInitializationWithProcessPool:configuration:] + 160
8   com.apple.WebKit              	0x0000000106dc307d -[WKContentView initWithFrame:processPool:configuration:wkView:] + 280
9   com.apple.WebKit              	0x0000000106e04925 -[WKView _commonInitializationWithContextRef:pageGroupRef:relatedToPage:] + 620
10  com.apple.WebKit              	0x0000000106e05212 -[WKView(Private) initWithFrame:contextRef:pageGroupRef:relatedToPage:] + 125
11  com.apple.WebKit              	0x0000000106e0518f -[WKView(Private) initWithFrame:contextRef:pageGroupRef:] + 59
12  org.webkit.WebKitTestRunnerApp0	0x00000001041d7d5b -[TestRunnerWKView initWithFrame:contextRef:pageGroupRef:relatedToPage:useTiledDrawing:] + 85 (PlatformWebViewIOS.mm:59)
13  org.webkit.WebKitTestRunnerApp0	0x00000001041d80ba WTR::PlatformWebView::PlatformWebView(OpaqueWKContext const*, OpaqueWKPageGroup const*, OpaqueWKPage const*, OpaqueWKDictionary const*) + 268 (PlatformWebViewIOS.mm:133)
14  org.webkit.WebKitTestRunnerApp0	0x00000001041cc64a WTR::TestController::createWebViewWithOptions(OpaqueWKDictionary const*) + 68 (memory:2627)
15  org.webkit.WebKitTestRunnerApp0	0x00000001041cafdc WTR::TestController::initialize(int, char const**) + 3242 (TestController.cpp:437)
16  org.webkit.WebKitTestRunnerApp0	0x00000001041ca1a0 WTR::TestController::TestController(int, char const**) + 306 (TestController.cpp:128)
17  org.webkit.WebKitTestRunnerApp0	0x00000001041c99c8 -[WebKitTestRunnerApp _runTestController] + 40 (mainIOS.mm:44)
18  com.apple.Foundation          	0x0000000106477d06 __NSThreadPerformPerform + 283
19  com.apple.CoreFoundation      	0x00000001079f4701 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
20  com.apple.CoreFoundation      	0x00000001079ea29c __CFRunLoopDoSources0 + 476
21  com.apple.CoreFoundation      	0x00000001079e97b8 __CFRunLoopRun + 856
22  com.apple.CoreFoundation      	0x00000001079e91d8 CFRunLoopRunSpecific + 488
23  com.apple.GraphicsServices    	0x00000001081abbb1 GSEventRunModal + 161
24  com.apple.UIKit               	0x00000001052f13a7 UIApplicationMain + 1215
25  org.webkit.WebKitTestRunnerApp0	0x00000001041c9c89 main + 32 (mainIOS.mm:81)
26  libdyld.dylib                 	0x000000010b8d0a05 start + 1

Attempted a follow-up fix by adding a NULL check in r181548:
<http://trac.webkit.org/r181548>