Given path/to/foo.mojom, change the code generator to output:

  <(SHARED_INTERMEDIATE_DIR)/path/to/foo.mojom.cc
  <(SHARED_INTERMEDIATE_DIR)/path/to/foo.mojom.h
  <(SHARED_INTERMEDIATE_DIR)/path/to/foo.mojom-internal.h

This involves shelling out to a python script to compute "path/to" part as that is not otherwise available from GYP. See build/inverse_depth.py.

DEPTH is now passed to mojom_bindings_generator.py so that it can similarly compute "path/to". With that, we no longer need the include_dir argument, so I dropped it.

R=davemoore@chromium.org, mark@chromium.org

Review URL: https://codereview.chromium.org/177183002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@253937 0039d316-1c4b-4281-b951-d872f2087c98