[metatracing] Add support for UI and categories

With this change, users can switch lightweight high-level always-on
metatracing from the UI, ensuring that it's easy to see which queries
have contributed to slow loading.

R=lalitm@google.com, hjd@google.com

Change-Id: I71eb1a4726d1b1eaf6ce9268ff1124f69e5bfcc9
diff --git a/Android.bp b/Android.bp
index 580d90f..aec2169 100644
--- a/Android.bp
+++ b/Android.bp
@@ -6647,6 +6647,7 @@
 genrule {
     name: "perfetto_protos_perfetto_trace_processor_zero_gen",
     srcs: [
+        "protos/perfetto/trace_processor/metatrace_categories.proto",
         "protos/perfetto/trace_processor/trace_processor.proto",
     ],
     tools: [
@@ -6655,6 +6656,7 @@
     ],
     cmd: "mkdir -p $(genDir)/external/perfetto/ && $(location aprotoc) --proto_path=external/perfetto --plugin=protoc-gen-plugin=$(location protozero_plugin) --plugin_out=wrapper_namespace=pbzero:$(genDir)/external/perfetto/ $(in)",
     out: [
+        "external/perfetto/protos/perfetto/trace_processor/metatrace_categories.pbzero.cc",
         "external/perfetto/protos/perfetto/trace_processor/trace_processor.pbzero.cc",
     ],
 }
@@ -6663,6 +6665,7 @@
 genrule {
     name: "perfetto_protos_perfetto_trace_processor_zero_gen_headers",
     srcs: [
+        "protos/perfetto/trace_processor/metatrace_categories.proto",
         "protos/perfetto/trace_processor/trace_processor.proto",
     ],
     tools: [
@@ -6671,6 +6674,7 @@
     ],
     cmd: "mkdir -p $(genDir)/external/perfetto/ && $(location aprotoc) --proto_path=external/perfetto --plugin=protoc-gen-plugin=$(location protozero_plugin) --plugin_out=wrapper_namespace=pbzero:$(genDir)/external/perfetto/ $(in)",
     out: [
+        "external/perfetto/protos/perfetto/trace_processor/metatrace_categories.pbzero.h",
         "external/perfetto/protos/perfetto/trace_processor/trace_processor.pbzero.h",
     ],
     export_include_dirs: [