Add a missing TODO.

Test: atest cts/tests/BlobStore/src/com/android/cts/blob/BlobStoreManagerTest.java
Change-Id: Ib7f48d845cf7984469c5f67e34f9cbca80823bf0

apct-tests/perftests/blobstore/src/com/android/perftests/blob/BlobStorePerfTests.java

@@ -102,7 +102,7 @@ public class BlobStorePerfTests {
 
                 durations.clear();
                 collectDigestDurationsFromTrace(parser, durations);
-                // get and delete blobId
+                // TODO: get and delete blobId before next iteration.
             }
         } finally {
             mAtraceUtils.stopTrace();