Add ResTable_sparseTypeEntry support

Benchmarks on bullhead-userdebug show that there is a negligent
performance impact when using sparse entries on a 30% loaded
sparse type of 1000 resources.

Benchmark                                             Time           CPU Iterations
-----------------------------------------------------------------------------------
BM_SparseEntryGetResourceSparseLarge                255 ns        254 ns    2751408
BM_SparseEntryGetResourceNotSparseLarge             254 ns        254 ns    2756534

Bug: 27381711
Test: make libandroidfw_tests aapt2_tests
Change-Id: I051ea22f2f6b2bc3696e446adc9e2a34be18009f

1 files changed, 3 insertions, 1 deletions

diff --git a/tools/aapt2/LoadedApk.cpp b/tools/aapt2/LoadedApk.cpp
index 3d7bd9479ad8..407550b112dc 100644
--- a/tools/aapt2/LoadedApk.cpp
+++ b/tools/aapt2/LoadedApk.cpp
@@ -94,7 +94,9 @@ bool LoadedApk::WriteToArchive(IAaptContext* context, IArchiveWriter* writer) {
     // The resource table needs to be reserialized since it might have changed.
     if (path == "resources.arsc") {
       BigBuffer buffer = BigBuffer(1024);
-      TableFlattener flattener(&buffer);
+      // TODO(adamlesinski): How to determine if there were sparse entries (and if to encode
+      // with sparse entries) b/35389232.
+      TableFlattener flattener({}, &buffer);
       if (!flattener.Consume(context, table_.get())) {
         return false;
       }