Added more checks to SafeStackFrameIterator to prevent crashes when profiling. Tested by profiling 3d-morph.js a 100 times both in debug and release builds.
Added more checks to SafeStackFrameIterator to prevent crashes when profiling.
Tested by profiling 3d-morph.js a 100 times both in debug and release builds.

Review URL: http://codereview.chromium.org/42600

git-svn-id: b158db1e4b4ab85d4c9e510fdef4b1e8c614b15b@1611 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh