IonHeapSize is replacing SystemIonHeapSize on devices with newer kernels. It relies on libmeminfo to measure the total size of all ion heaps, unlike the old atom that manually parsed a file from debugfs. Test: m -j Test: statsd_testdrive 10070 Bug: 140788538 Bug: 147722878 Change-Id: If3fa74bd96631116ef05656e7942fa6cf4e15005