ParserWindowManagerDump more robust to invalid input

ParserWindowManagerDump is prone to accepting invalid inputs because it lacks a magic number check.
This commit reduces changes of accepting invalid inputs by making sure that the parser is actually
able to create a trace entry from the decoded proto.

Test: npm run build:unit && npm run test:unit
Change-Id: I1aad12387ce064cde6e27e09cd6d329bb21f5066
3 files changed