Pull system ion heap size.

Test: m -j
Test: atest MemoryStatUtilTest
Bug: 128412961
Change-Id: I9a12b03ef92d0df067253fee5165107586bdad54
diff --git a/stats/atoms.proto b/stats/atoms.proto
index b812c80..d9b8ab4 100644
--- a/stats/atoms.proto
+++ b/stats/atoms.proto
@@ -252,7 +252,7 @@
     }
 
     // Pulled events will start at field 10000.
-    // Next: 10056
+    // Next: 10057
     oneof pulled {
         WifiBytesTransfer wifi_bytes_transfer = 10000;
         WifiBytesTransferByFgBg wifi_bytes_transfer_by_fg_bg = 10001;
@@ -310,6 +310,7 @@
         SDCardInfo sdcard_info = 10053;
         GpuStatsGlobalInfo gpu_stats_global_info = 10054;
         GpuStatsAppInfo gpu_stats_app_info = 10055;
+        SystemIonHeapSize system_ion_heap_size = 10056;
     }
 
     // DO NOT USE field numbers above 100,000 in AOSP.
@@ -5783,3 +5784,13 @@
     // List of all the Vulkan driver laoding times for this app.
     repeated int64 vk_driver_loading_time = 4;
 }
+
+/*
+ * Logs the size of the system ion heap.
+ *
+ * Pulled from StatsCompanionService.
+ */
+message SystemIonHeapSize {
+    // Size of the system ion heap in bytes.
+    optional int64 size_in_bytes = 1;
+}