DynamicPartitionControl: Add required_size to Prepare

Add out parameter required_size to PreparePartitionsForUpdate
to indicate the total size required on /userdata in order
to apply the update.

Bug: 138808058
Test: update_engine_unittests

Change-Id: I2768d13671e212fd24a1a22811b50c9738834459
diff --git a/mock_dynamic_partition_control.h b/mock_dynamic_partition_control.h
index 09b825d..ffabac7 100644
--- a/mock_dynamic_partition_control.h
+++ b/mock_dynamic_partition_control.h
@@ -38,8 +38,9 @@
                     std::string*));
   MOCK_METHOD0(Cleanup, void());
   MOCK_METHOD0(GetDynamicPartitionsFeatureFlag, FeatureFlag());
-  MOCK_METHOD4(PreparePartitionsForUpdate,
-               bool(uint32_t, uint32_t, const DeltaArchiveManifest&, bool));
+  MOCK_METHOD5(
+      PreparePartitionsForUpdate,
+      bool(uint32_t, uint32_t, const DeltaArchiveManifest&, bool, uint64_t*));
   MOCK_METHOD0(GetVirtualAbFeatureFlag, FeatureFlag());
   MOCK_METHOD0(FinishUpdate, bool());
 };