I often ends up with a corrupt toolchain because I've used Windbg and there's now a bunch of PDB files in win_sdk/Debuggers/sym/... , I think that it's safe to ignore these files (the original package doesn't contain any of these files).

It's also useful to have more details about which files are missing and or which ones shouldn't be here when we get an invalid toolchain hash.

Finally, if you the hash of a toolchain doesn't correspond to the name of its root directory then it should be removed.

Review-Url: https://codereview.chromium.org/1974453003

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@300557 0039d316-1c4b-4281-b951-d872f2087c98