Crash Portal server processes 2 types of crash dump files

Minidumps

Minidump files are a lightweight crash dump format developed by Microsoft.
Google Breakpad project supplies tools to work with Minidump files.
The primary tool used by Crash Portal is minidump_stackwalk which generates a stack trace from a minidump file.
See http://www.chromium.org/developers/decoding-crash-dumps

Coredumps

Coredump files are standard Linux coredumps.
Crash Portal extracts information from the coredump files but does not generate a stack trace.
- But a tool such as gdb will do this.

Minidump or core files are tarred and uploaded by crashUpload component:

...

PORTAL_URL="35.155.171.121:80"
REQUEST_TYPE=17