This change splits the generate_snapshot_file build target into two targets:
generate_snapshot_bin - executes gen_snapshot to create snapshot_bin_file
generate_snapshot_file - creates snapshot_cc_file
It's not strictly necessary to split the generation into two steps, but
it is convenient to do so, because only the first step needs to know about
Android. The second step can be shared between all builds.
For Android we copy the gen_snapshot executable and all its input files
to Android, run it there, and copy the output files back to the host.
Review URL: https://chromiumcodereview.appspot.com//10827250
git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@10676 260f80e4-7a28-3924-810f-c04153c831b5
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