Support compose with quoted html.

ComposeActivity now can be started with EXTRA_QUOTED_TEXT
or EXTRA_HTML_TEXT which will place text into the quoted
region automatically. Goes towards fixing b/6373710 but
using EXTRA_HTML_TEXT has not yet been tested.

Change-Id: I795a0141603670891ccc09a65b2432c0f8db95c8
4 files changed