Yes, I am getting precisely the same error, I believe the error is that the particular commit, ie. 904fcf74a1282b5715c20deb73c5f33a64026d2f is not present. What I did was :
cd chromium/src/third_party/akia
git reset --hard HEAD
I believe that although this should not create issues while building (not tested), it will still create skia error when anyone tries to "gclient sync".
PS. I am a beginner in Chromium Development, and I am using arch and hence I did not run the "install-build-deps.sh" script, I had to manually install packages as mentioned in notes. I don't know whether this contributes to the issue.