Count cache in storage categories.

This makes the System size more consistent because cache is not
attributed to the system (when the cache is under quota).

Change-Id: I680e70daf5e98b9a205023a218dfd1dcc8ee8334
Fixes: 62623731
Test: Settings Unit Test

src/com/android/settings/deviceinfo/storage/StorageAsyncLoader.java

@@ -105,7 +105,17 @@ public class StorageAsyncLoader
                 continue;
             }
 
-            long blamedSize = stats.getDataBytes() - stats.getCacheBytes();
+            final long dataSize = stats.getDataBytes();
+            final long cacheQuota = mStatsManager.getCacheQuotaBytes(mUuid, app.uid);
+            final long cacheBytes = stats.getCacheBytes();
+            long blamedSize = dataSize;
+            // Technically, we could overages as freeable on the storage settings screen.
+            // If the app is using more cache than its quota, we would accidentally subtract the
+            // overage from the system size (because it shows up as unused) during our attribution.
+            // Thus, we cap the attribution at the quota size.
+            if (cacheQuota < cacheBytes) {
+                blamedSize = blamedSize - cacheBytes + cacheQuota;
+            }
 
             // This isn't quite right because it slams the first user by user id with the whole code
             // size, but this ensures that we count all apps seen once.