Changeset 244113 in webkit

Timestamp:

Apr 10, 2019 9:32:30 AM (5 years ago)

Author:

beidson@apple.com

Message:

Background tabs are not fully reactivated after a link is opened from an external application.
<rdar://problem/49533278> and ​https://bugs.webkit.org/show_bug.cgi?id=196705

Reviewed by Chris Dumez.

If an app unparents a WKWebView right after activation but before the "applicationWillEnterForeground" notification
is dispatched, then that WKWebView is in a broken state with a frozen layer tree.

The WKApplicationStateTrackingView logic needs to be a little more resilient.

• UIProcess/ios/WKApplicationStateTrackingView.mm:

(-[WKApplicationStateTrackingView willMoveToWindow:]): When clearing the window, remember the current background state.
(-[WKApplicationStateTrackingView didMoveToWindow]): If our last observed background state doesn't match the current

background state then fake the relevant notification.

(-[WKApplicationStateTrackingView _applicationDidEnterBackground]): Remember that we've observed a backgrounding.
(-[WKApplicationStateTrackingView _applicationWillEnterForeground]): Remember that we've observed a foregrounding.

Location:

trunk/Source/WebKit

Files:

• ChangeLog (modified) (1 diff)
• UIProcess/ios/WKApplicationStateTrackingView.mm (modified) (5 diffs)

trunk/Source/WebKit/ChangeLog

@@ +1 @@
+2019-04-10  Brady Eidson  <beidson@apple.com>
+
+        Background tabs are not fully reactivated after a link is opened from an external application.
+        <rdar://problem/49533278> and https://bugs.webkit.org/show_bug.cgi?id=196705
+
+        Reviewed by Chris Dumez.
+
+        If an app unparents a WKWebView right after activation but before the "applicationWillEnterForeground" notification
+        is dispatched, then that WKWebView is in a broken state with a frozen layer tree.
+
+        The WKApplicationStateTrackingView logic needs to be a little more resilient.
+
+        * UIProcess/ios/WKApplicationStateTrackingView.mm:
+        (-[WKApplicationStateTrackingView willMoveToWindow:]): When clearing the window, remember the current background state.
+        (-[WKApplicationStateTrackingView didMoveToWindow]): If our last observed background state doesn't match the current
+          background state then fake the relevant notification.
+        (-[WKApplicationStateTrackingView _applicationDidEnterBackground]): Remember that we've observed a backgrounding.
+        (-[WKApplicationStateTrackingView _applicationWillEnterForeground]): Remember that we've observed a foregrounding.
+
 2019-04-10  Diego Pino Garcia  <dpino@igalia.com>
 

trunk/Source/WebKit/UIProcess/ios/WKApplicationStateTrackingView.mm

@@ -38 +38 @@
     WeakObjCPtr<WKWebView> _webViewToTrack;
     std::unique_ptr<WebKit::ApplicationStateTracker> _applicationStateTracker;
+    BOOL _lastObservedStateWasBackground;
 }
 
@@ -54 +55 @@
         return;
 
+    _lastObservedStateWasBackground = [self isBackground];
+
     ASSERT(_applicationStateTracker);
     _applicationStateTracker = nullptr;
@@ -65 +68 @@
     ASSERT(!_applicationStateTracker);
     _applicationStateTracker = std::make_unique<WebKit::ApplicationStateTracker>(self, @selector(_applicationDidEnterBackground), @selector(_applicationDidFinishSnapshottingAfterEnteringBackground), @selector(_applicationWillEnterForeground));
+    
+    if (_lastObservedStateWasBackground && ![self isBackground])
+        [self _applicationWillEnterForeground];
+    else if (!_lastObservedStateWasBackground && [self isBackground])
+        [self _applicationDidEnterBackground];
 }
 
@@ -73 +81 @@
         return;
 
+    _lastObservedStateWasBackground = YES;
     page->applicationDidEnterBackground();
     page->activityStateDidChange(WebCore::ActivityState::allFlags() - WebCore::ActivityState::IsInWindow);
@@ -89 +98 @@
         return;
 
+    _lastObservedStateWasBackground = NO;
     page->applicationWillEnterForeground();
     page->activityStateDidChange(WebCore::ActivityState::allFlags() - WebCore::ActivityState::IsInWindow, true, WebKit::WebPageProxy::ActivityStateChangeDispatchMode::Immediate);