3a6e0ec223
The previous default location of "/sdcard" became painful to use starting in M, because it required a runtime permission. So now we default to storing trace files in app-specific directories on shared storage, which apps always have write access to with no additional permissions. Update docs to be consistent between all overloads. Bug: 22807654 Change-Id: If4feca7c8778dfdf4ccce8cfb68418dc416260b5