Implement support for transcoding WOFF fonts.

Implement support for transcoding WOFF fonts.

Not all the test utilities will work with WOFF fonts since they tend
to get a lot larger after transcoding. I've updated |idempotent|, but
none of the others as our test suites of fonts are still in TTF format.

[Yusuke Sato, 2010-04-28 18:17:33]

Thanks a lot for the nice and quick work! Some minor comments below:

http://codereview.appspot.com/946044/diff/3001/4001
File include/ots-memory-stream.h (right):

http://codereview.appspot.com/946044/diff/3001/4001#newcode79
include/ots-memory-stream.h:79: ptr_ = new_buf;
please delete[] ptr_ before assignment.

http://codereview.appspot.com/946044/diff/3001/4002
File src/ots.cc (right):

http://codereview.appspot.com/946044/diff/3001/4002#newcode15
src/ots.cc:15: #include <zlib.h>
nitpick: please move this to L.8.

http://codereview.appspot.com/946044/diff/3001/4002#newcode83
src/ots.cc:83: i = hunks_.begin(); i != hunks_.end(); i++) {
nitpick: ++i

http://codereview.appspot.com/946044/diff/3001/4002#newcode278
src/ots.cc:278: // We don't care about these fields of the header:
It's up to you, but how about checking the value of the reserved field?

The spec says "this MUST be set to zero. If this field is non-zero, a WOFF
processor conforming to this specification MUST reject the file as invalid."

http://codereview.appspot.com/946044/diff/3001/4002#newcode356
src/ots.cc:356: // disallow all tables which uncompress to > 16 MB
16MB might be too small? Please see my comment below.

http://codereview.appspot.com/946044/diff/3001/4002#newcode375
src/ots.cc:375: if (uncompressed_sum > 16 * 1024 * 1024) {
Some of unmalicious fonts seem to exceed this limitation. How about using 30MB
or something?

fonts$ find . -size +16M -name '*tf' -ls
-rwxr-xr-x   1 yusukes        27382464 Aug 25  2009 ./windows/mingliu0.ttf
-rwxr-xr-x   1 yusukes        27382472 Aug 25  2009 ./windows/mingliu1.ttf
-rwxr-xr-x   1 yusukes        27396928 Aug 25  2009 ./windows/mingliu2.ttf
-rwxr-xr-x   1 yusukes        23278008 Jul  1  2009 ./mac/Arial\ Unicode.ttf

If I recall correctly, the limitation in OpenTypeSanitizer::sanitize() was 30MB.

[Yusuke Sato, 2010-04-28 20:00:27]

Adding chromium-reviews just in case.