This allows writing native tests for non-A/B update_binary_command().
Prior to this CL, it was extracting the updater to a hard-coded
location (/tmp/update_binary) that's not available under the test
environment.
Test: recovery_component_test on angler and marlin respectively.
Test: Sideload OTA packages on angler and marlin respectively.
Change-Id: I78b9cc211d90c0a16a84e94e339b65759300e2a8
Expose update_binary_command() through private/install.h for testing
purpose.
Also make minor clean-ups to install.cpp: a) adding more verbose logging
on ExtractToMemory failures; b) update_binary_command() taking
std::string instead of const char*; c) moving a few macro and global
constants into update_binary_command().
Bug: 37300957
Test: recovery_component_test on marlin
Test: Build new recovery and adb sideload on angler and sailfish.
Change-Id: Ib2d9068af3fee038f01c90940ccaeb0a7da374fc