tp: move metadata, perf sample and stack trackers to improters/proto

Change-Id: Ie08312f919718634c5923bcbdfa23bcbceec91af
diff --git a/BUILD b/BUILD
index d143300..bba8d0d 100644
--- a/BUILD
+++ b/BUILD
@@ -983,8 +983,6 @@
         "src/trace_processor/event_tracker.h",
         "src/trace_processor/forwarding_trace_parser.cc",
         "src/trace_processor/forwarding_trace_parser.h",
-        "src/trace_processor/heap_profile_tracker.cc",
-        "src/trace_processor/heap_profile_tracker.h",
         "src/trace_processor/importers/common/args_tracker.cc",
         "src/trace_processor/importers/common/args_tracker.h",
         "src/trace_processor/importers/common/global_args_tracker.cc",
@@ -1005,8 +1003,14 @@
         "src/trace_processor/importers/ninja/ninja_log_parser.h",
         "src/trace_processor/importers/proto/args_table_utils.cc",
         "src/trace_processor/importers/proto/args_table_utils.h",
+        "src/trace_processor/importers/proto/heap_profile_tracker.cc",
+        "src/trace_processor/importers/proto/heap_profile_tracker.h",
+        "src/trace_processor/importers/proto/metadata_tracker.cc",
+        "src/trace_processor/importers/proto/metadata_tracker.h",
         "src/trace_processor/importers/proto/packet_sequence_state.cc",
         "src/trace_processor/importers/proto/packet_sequence_state.h",
+        "src/trace_processor/importers/proto/perf_sample_tracker.cc",
+        "src/trace_processor/importers/proto/perf_sample_tracker.h",
         "src/trace_processor/importers/proto/profile_module.cc",
         "src/trace_processor/importers/proto/profile_module.h",
         "src/trace_processor/importers/proto/profile_packet_utils.cc",
@@ -1018,6 +1022,8 @@
         "src/trace_processor/importers/proto/proto_trace_parser.h",
         "src/trace_processor/importers/proto/proto_trace_tokenizer.cc",
         "src/trace_processor/importers/proto/proto_trace_tokenizer.h",
+        "src/trace_processor/importers/proto/stack_profile_tracker.cc",
+        "src/trace_processor/importers/proto/stack_profile_tracker.h",
         "src/trace_processor/importers/proto/track_event_module.cc",
         "src/trace_processor/importers/proto/track_event_module.h",
         "src/trace_processor/importers/proto/track_event_parser.cc",
@@ -1026,14 +1032,8 @@
         "src/trace_processor/importers/proto/track_event_tokenizer.h",
         "src/trace_processor/importers/syscalls/syscall_tracker.h",
         "src/trace_processor/importers/systrace/systrace_line.h",
-        "src/trace_processor/metadata_tracker.cc",
-        "src/trace_processor/metadata_tracker.h",
-        "src/trace_processor/perf_sample_tracker.cc",
-        "src/trace_processor/perf_sample_tracker.h",
         "src/trace_processor/slice_tracker.cc",
         "src/trace_processor/slice_tracker.h",
-        "src/trace_processor/stack_profile_tracker.cc",
-        "src/trace_processor/stack_profile_tracker.h",
         "src/trace_processor/status_macros.h",
         "src/trace_processor/timestamped_trace_piece.h",
         "src/trace_processor/trace_blob_view.h",