Exceptions in UIWebView on dealloc when displaying PDFs.

gistfile1.txt

* thread #1: tid = 0x1c03, 0x37447724 libc++abi.dylib`__cxa_throw, stop reason = breakpoint 1.1
    frame #0: 0x37447724 libc++abi.dylib`__cxa_throw
    frame #1: 0x330fe296 libobjc.A.dylib`objc_exception_throw + 94
    frame #2: 0x37dcd788 CoreFoundation`+[NSException raise:format:arguments:] + 100
    frame #3: 0x37dcd7aa CoreFoundation`+[NSException raise:format:] + 34
    frame #4: 0x36f9a618 Foundation`-[NSObject(NSKeyValueObserverRegistration) _removeObserver:forProperty:] + 740
    frame #5: 0x36f9a286 Foundation`-[NSObject(NSKeyValueObserverRegistration) removeObserver:forKeyPath:] + 170
    frame #6: 0x30f4799c UIKit`-[UIWebPDFView _removeBackgroundImageObserverIfNeeded:] + 108
    frame #7: 0x30f47bfc UIKit`-[UIWebPDFView dealloc] + 540
    frame #8: 0x330fa174 libobjc.A.dylib`_objc_rootRelease + 36
    frame #9: 0x30d4ff14 UIKit`-[UIWebPDFViewHandler clearAllViews] + 156
    frame #10: 0x30d4fe3c UIKit`-[UIWebPDFViewHandler dealloc] + 72
    frame #11: 0x330fa174 libobjc.A.dylib`_objc_rootRelease + 36
    frame #12: 0x30d4fc5a UIKit`-[UIWebView dealloc] + 282
    frame #13: 0x30d4e1a2 UIKit`-[UIWebView release] + 178
    frame #14: 0x330fbe56 libobjc.A.dylib`objc_release + 38
    frame #15: 0x33107c06 libobjc.A.dylib`objc_storeStrong + 30
    frame #16: 0x0027dbb2 seek`-[SKWebView .cxx_destruct](self=0x11081060, _cmd=0x0027db09) + 170 at SKWebView.m:35
    frame #17: 0x330fcb0c libobjc.A.dylib`object_cxxDestructFromClass + 56
    frame #18: 0x330fcad2 libobjc.A.dylib`object_cxxDestruct + 14
    frame #19: 0x330faa52 libobjc.A.dylib`objc_destructInstance + 26
    frame #20: 0x330fad72 libobjc.A.dylib`object_dispose + 14
    frame #21: 0x37d2361e CoreFoundation`-[NSObject dealloc] + 82
    frame #22: 0x30bd0206 UIKit`-[UIView dealloc] + 626
    frame #23: 0x0027a6aa seek`-[SKWebView dealloc](self=0x11081060, _cmd=0x37add2da) + 86 at SKWebView.m:70
    frame #24: 0x330fa174 libobjc.A.dylib`_objc_rootRelease + 36
    frame #25: 0x330fbe56 libobjc.A.dylib`objc_release + 38
    frame #26: 0x33107c06 libobjc.A.dylib`objc_storeStrong + 30
    frame #27: 0x00286d9e seek`-[ResumePreviewViewController .cxx_destruct](self=0x0098d210, _cmd=0x00286c59) + 326 at ResumePreviewViewController.m:29
    frame #28: 0x330fcb0c libobjc.A.dylib`object_cxxDestructFromClass + 56
    frame #29: 0x330fcad2 libobjc.A.dylib`object_cxxDestruct + 14
    frame #30: 0x330faa52 libobjc.A.dylib`objc_destructInstance + 26
    frame #31: 0x330fad72 libobjc.A.dylib`object_dispose + 14
    frame #32: 0x37d2361e CoreFoundation`-[NSObject dealloc] + 82
    frame #33: 0x30c7122c UIKit`-[UIViewController dealloc] + 1036
    frame #34: 0x00281f90 seek`-[ResumePreviewViewController dealloc](self=0x0098d210, _cmd=0x37add2da) + 84 at ResumePreviewViewController.m:75
    frame #35: 0x330fa174 libobjc.A.dylib`_objc_rootRelease + 36
    frame #36: 0x330fbe56 libobjc.A.dylib`objc_release + 38
    frame #37: 0x330faeac libobjc.A.dylib`(anonymous namespace)::AutoreleasePoolPage::pop(void*) + 224
    frame #38: 0x330fadc8 libobjc.A.dylib`_objc_autoreleasePoolPop + 12
    frame #39: 0x37d1dcfe CoreFoundation`_CFAutoreleasePoolPop + 18
    frame #40: 0x30bb6c92 UIKit`_wrapRunLoopWithAutoreleasePoolHandler + 42
    frame #41: 0x37da1b1a CoreFoundation`__CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 18
    frame #42: 0x37d9fd56 CoreFoundation`__CFRunLoopDoObservers + 258
    frame #43: 0x37da00b0 CoreFoundation`__CFRunLoopRun + 760
    frame #44: 0x37d234a4 CoreFoundation`CFRunLoopRunSpecific + 300
    frame #45: 0x37d2336c CoreFoundation`CFRunLoopRunInMode + 104
    frame #46: 0x36206438 GraphicsServices`GSEventRunModal + 136
    frame #47: 0x30bd4cd4 UIKit`UIApplicationMain + 1080
    frame #48: 0x000aee26 seek`main(argc=1, argv=0x2feaab48) + 98 at main.m:9

This exception seems to be consumed by UIWebView.