Change the backtrace view into a process tree view where you can expand the process, its threads and see all frames under each thread. 
Change the backtrace view into a process tree view where you can expand the process, its threads and see all frames under each thread. 



git-svn-id: 4c4cc70b1ef44ba2b7963015e681894188cea27e@204251 91177308-0d34-0410-b5e6-96231b3b80d8

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