Drop the dependency on AB_OTA_UPDATER flag.

This shortens the gap between A/B and non-A/B builds, by replacing the
dependency on build-time flag with runtime detection instead. It also
allows building and testing both paths regardless of the target OTA
type.

The size increase to /sbin/recovery looks negligible (< 0.01%).
 - marlin: increased from 2084928 to 2085024;
 - angler: increased from 2084776 to 2084896.

Test: Run recovery_component_test on angler and marlin.
Test: Sideload an A/B OTA package on marlin.
Test: Sideload a non-A/B OTA package on angler.
Change-Id: I1d927d1ede9713fb42f73b4fe324aa5705ee6f99
diff --git a/private/install.h b/private/install.h
index ef64bd4..7fdc741 100644
--- a/private/install.h
+++ b/private/install.h
@@ -23,9 +23,17 @@
 
 #include <ziparchive/zip_archive.h>
 
-// Extract the update binary from the open zip archive |zip| located at |package| to |binary_path|.
-// Store the command line that should be called into |cmd|. The |status_fd| is the file descriptor
-// the child process should use to report back the progress of the update.
-int update_binary_command(const std::string& package, ZipArchiveHandle zip,
-                          const std::string& binary_path, int retry_count, int status_fd,
+// Sets up the commands for a non-A/B update. Extracts the updater binary from the open zip archive
+// |zip| located at |package|. Stores the command line that should be called into |cmd|. The
+// |status_fd| is the file descriptor the child process should use to report back the progress of
+// the update.
+int SetUpNonAbUpdateCommands(const std::string& package, ZipArchiveHandle zip, int retry_count,
+                             int status_fd, std::vector<std::string>* cmd);
+
+// Sets up the commands for an A/B update. Extracts the needed entries from the open zip archive
+// |zip| located at |package|. Stores the command line that should be called into |cmd|. The
+// |status_fd| is the file descriptor the child process should use to report back the progress of
+// the update. Note that since this applies to the sideloading flow only, it takes one less
+// parameter |retry_count| than the non-A/B version.
+int SetUpAbUpdateCommands(const std::string& package, ZipArchiveHandle zip, int status_fd,
                           std::vector<std::string>* cmd);