trace_processor: add bitvector implementation

The trace processor refactor will make heavy use of this class for
sort, filter and SparseVector logic.

Bug: 135177627
Change-Id: Ib687be1d319377bc2db6bfe19762834bd24b4d15
diff --git a/src/trace_processor/BUILD.gn b/src/trace_processor/BUILD.gn
index e7b4a97..adb357b 100644
--- a/src/trace_processor/BUILD.gn
+++ b/src/trace_processor/BUILD.gn
@@ -191,6 +191,7 @@
     "../../protos/perfetto/trace/track_event:zero",
     "../base",
     "../protozero",
+    "db:lib",
     "metrics:lib",
   ]
   public_deps = [
@@ -276,6 +277,7 @@
     "../../protos/perfetto/trace/track_event:zero",
     "../base",
     "../protozero",
+    "db:unittests",
   ]
   if (perfetto_build_standalone || build_with_chromium) {
     sources += [