[trace_processor] New base class for proto importer modules

This CL introduces a new virtual base class for proto importer modules
that allows to register modules for specific fields at runtime.
The GraphicsEventModule is migrated to the new base class.

Bug: 141459049
Change-Id: I78370b1b3f1015cf5df9fdb9cf8435061c8bc947
diff --git a/Android.bp b/Android.bp
index b722a95..6c5cbcc2 100644
--- a/Android.bp
+++ b/Android.bp
@@ -4761,10 +4761,12 @@
     "src/trace_processor/importers/fuchsia/fuchsia_trace_utils.cc",
     "src/trace_processor/importers/proto/android_probes_parser.cc",
     "src/trace_processor/importers/proto/args_table_utils.cc",
+    "src/trace_processor/importers/proto/graphics_event_module.cc",
     "src/trace_processor/importers/proto/graphics_event_parser.cc",
     "src/trace_processor/importers/proto/heap_graph_module.cc",
     "src/trace_processor/importers/proto/heap_graph_tracker.cc",
     "src/trace_processor/importers/proto/heap_graph_walker.cc",
+    "src/trace_processor/importers/proto/proto_importer_module.cc",
     "src/trace_processor/importers/proto/proto_trace_parser.cc",
     "src/trace_processor/importers/proto/proto_trace_tokenizer.cc",
     "src/trace_processor/importers/proto/system_probes_parser.cc",