Am I reading the travis failures correctly that the build is just timing out because the license script is taking > 10 minutes?

Yes - it looks like the license script froze in the middle of processing Skia sources. Try restarting the Travis job.

Hmm. I re-ran job, and it failed in the same way. Guess I'll try running it locally to see if something in the Skia tree is causing the script to choke.

... and it stalls locally as well. Interesting note: We've recently modified how we write/build shaders in Ganesh. We have a custom language for the shader source code, and a tool that emits C++ headers and source files from those. We have the C++ code checked in, so that clients don't need to modify their build process, but those files are definitely not formatted like the rest of our code (line length and indentation are both pretty bizarre). The file that's causing the hang is one of those files (and probably the first one being encountered by the script). I've just started looking at the details of the license script, but my dart knowledge is pretty minimal. I'm wondering if one of the regular expressions has some bad construct that we're triggering with the formatting of our generated source?

Which file path specifically is hanging? @jason-simmons and @Hixie wrote the license script.

You could also consider just running clang-format on those files before checking them in? :)

It's hanging on src/effects/GrCircleBlurFragmentProcessor.cpp. The RegEx that it appears to be running (from breaking in with observatory) is below, but I don't see this particular pattern anywhere in the license script source code:
$ p _re = _RegExp (^((?:[-;@#<!.\\"/* ]*(?:REM[-;@#<!.\\"/* ]*)?[-;@#<!.\"/*]+)?)( *)(?:Portions *(?:(?:\*/ *|[*#])?(?:\n\1 *(?:\*/ *)?)*\n\1\2 *)?)

Running clang-format on that source file did prevent the hang, so we've landed that as a workaround, and I'm now going to roll Skia at that revision.

Multiple attempts at getting the sky license check to pass convinced me that I probably had stale third_party libs (that had been removed from DEPS?), so I just abandoned this and started with a fresh repo in #3884.