View inline images in photo viewer. b/5555553.

Uses the existing javascript image src rewriting
step to build a mapping of urls to message ids.

This mapping is passed into the InlineAttachmentViewIntentBuilder
so that it can use this information along with the
conversation id and account name to build attachment
and attachment list uris so that a photo viewer open
intent can be created.

Additionally, SecureConversationViewController will need a different
mechanism for this UI to work in Email/the eml viewer.

Change-Id: If14800348fe2191d0633bf768b8cb4e9746f6578
15 files changed