https://build.chromium.org/p/chromium.fyi/builders/ClangToTAndroid%20x64?numbuilds=200 builds 'all' to check that all targets build fine. It looks like this currently means "build all targets, with all toolchains".  The x64 Android build has a 64-bit and a 32-bit build, and has host and target toolchains -- as a result, the bot builds 71372 edges in a build (it's a clobber bot).  Before I switched it to building 'all', it build only "many" test binaries, which required 32997 edges. (Most edges of the host toolchains aren't needed, for example.)

I think 'all' shouldn't build all the targets with e.g. a host toolchain -- it makes more sense to me that 'all' should build everything with the default toolchain, and include all targets depended on explicitly in different toolchains (?)