remove hard-coded behavior for Android libraries,
replacing them with support for a new doclava option, "dac_libraryroot",
which specifies the path to this API's root URL (after accounting for
DAC's reference/ path). For example, the wearable doclava build must
specify libraryroot as "android/support/constraint/". Also required
is a unique name for array created inside lists.js, specified with the
"dac_dataname" option. For wearable, it is "SUPPORT_WEARABLE_DATA"

NOTES:
I would have used the -hdf flag to instead pass "dac_dataname" because
that's needed only in the clearsilver template, but I discovered that
you can't pass the same javadoc option more than once, and we already
use the -hdf option.
I also discovered some weird bug as a result of the way Gradle's javadoc
alphabetizes the options given, which resulted in javadoc errors when
either of these options were presented immediately before the -quiet
flag. So to avoid those errors, I prefixed each new option with "dac"
so as to make them appear much earlier in the javadoc command.

bug: 37319063
Change-Id: Ia33fca33b8597f6909c3142803525e729c81020c
5 files changed