Make mojom_data_tests.py exist and work again.

This undoes r230890 (which was an incorrect "completion" of another
revert), and updates mojom_data.py and mojom_data_tests.py to work
properly again.

(This does NOT add tests for the newer things.)

R=davemoore@chromium.org

Review URL: https://codereview.chromium.org/137203015

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@247001 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 247001
New incremental SPDY header parser.

New logic to parse SPDY headers as soon as they are available,
instead of waiting to receive the entire headers block first.

No behavioural change (the new logic introduced in this CL is not yet invoked).

This lands server change 59046509 by ygi.

Chromium specific: Add SpdyHeadersBlockParserReader & tests as an
alternative to the upstream's use of Chord (not supported). The
reader has the additional advantage of not copying header block
data, unless it's part of the remainder prefix for the next
invocation.

BUG=rch@chromium.org

Review URL: https://codereview.chromium.org/130503004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@247002 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 247002