Detector for Binder.clearCallingIdentity() bugs.

Binder maintains thread-local identity information about any remote
caller, which can be temporarily cleared while performing operations
that need to be handled as the current process. However, it's
important to restore the original remote calling identity after
carefully scoping this work inside a try/finally block, to avoid
obscure security vulnerabilities.

Bug: 155703208
Test: atest error_prone_android_framework_test
Change-Id: I568771a50af27637e4984950dcada2248ce16afe
3 files changed