Make drag and drop comply with cross profile copy paste policy

If UserManager.DISALLOW_CROSS_PROFILE_COPY_PASTE is false
then drag and drop is only possible between apps from the same
profile.

This CL also supports cross-profile content URI grants.

Bug:26772503
Change-Id: I2e160cfdc6259fee2ea5e561c6e21fc0547dca2e
2 files changed