Bug 123517

Summary: Remote Layer Tree: Lots of ASSERT(m_children.isEmpty()); on Poster Circle
Product: WebKit Reporter: Tim Horton <thorton>
Component: WebKit2Assignee: Tim Horton <thorton>
Status: RESOLVED FIXED    
Severity: Normal CC: andersca, simon.fraser
Priority: P2    
Version: 528+ (Nightly build)   
Hardware: Unspecified   
OS: Unspecified   
Attachments:
Description Flags
patch
none
no reason not to fold it into the existing loop simon.fraser: review+

Description Tim Horton 2013-10-30 11:12:02 PDT 
A recently added assertion discovered a bug where our dependence on undefined behavior in CA was causing the layer tree to get into a bad state. We depend on adding a sublayer which already has a parent to another layer, the sublayer is first removed from its parent layer. CA headers say this is undefined behavior (that layers should always have a nil superlayer when being added as a sublayer), but we heavily depend on it being the case.

Most of PlatformCALayerRemote behaved correctly, but setSublayers() failed to unparent the incoming layers.
Comment 1 Tim Horton 2013-10-30 11:14:17 PDT 
Created attachment 215533 [details]
patch
Comment 2 Tim Horton 2013-10-30 11:50:24 PDT 
Created attachment 215542 [details]
no reason not to fold it into the existing loop
Comment 3 Tim Horton 2013-10-30 11:58:06 PDT 
http://trac.webkit.org/changeset/158297