Replace libchrome size() with C++ standard ones am: 91aa21747d am: f0ec17a18b

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/3309624

Change-Id: I698a8a7eaf3dff298e2b435543c1b2a9d510e82d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>