Moves away from crufty char* operations to std::string utility
methods, including android::base methods for splitting/parsing.
Rewrite of how Process handles scanning procfs for filesystem
references; now uses fts(3) for more sane traversal.
Replace sscanf() with new FindValue() method, also has unit tests.
Remove some unused methods. Switch almost everyone over to using
modern logging library.
Test: cts-tradefed run commandAndExit cts-dev -m CtsOsTestCases -t android.os.storage.cts.StorageManagerTest
Test: cts-tradefed run commandAndExit cts-dev --abi armeabi-v7a -m CtsAppSecurityHostTestCases -t android.appsecurity.cts.AdoptableHostTest
Bug: 67041047
Change-Id: I70dc512f21459d1e25b187f24289002b2c7bc7af