Add some additional safety checks to the StructuredData access methods - lldb can still crash pretty easily on corrupt JSON text, and these will help eliminate a bunch of cases where that would result in a crash.  Some of the methods would check that e.g. GetItemAtIndex would actually return an item before dereferencing it, some would not, that kind of thing.  
Add some additional safety checks to the StructuredData access
methods - lldb can still crash pretty easily on corrupt JSON text,
and these will help eliminate a bunch of cases where that would
result in a crash.  Some of the methods would check that e.g.
GetItemAtIndex would actually return an item before dereferencing it,
some would not, that kind of thing.  

<rdar://problem/23768693> 


git-svn-id: 4c4cc70b1ef44ba2b7963015e681894188cea27e@255093 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-lldb,apple/swift-lldb,apple/swift-lldb,apple/swift-lldb,llvm-mirror/lldb,apple/swift-lldb,llvm-mirror/lldb,llvm-mirror/lldb,llvm-mirror/lldb,apple/swift-lldb,llvm-mirror/lldb