Make simple_json_parser a perfetto_component

[MichaelFQuigley]

Make simple_json_parser a perfetto_component.

This allows it to become a cc_library and be shared as a dependency in multiple
libraries while avoiding ODR violations.

This is in preparation for an upcoming change to parse JSON comments from
Proguard mapping (.map) files, such as:

# {"id":"com.android.tools.r8.mergedClasses", "class_id_field": "$cid", "merged_classes": [{ "name": "ClassA", "class_id": 0 }, { "name": "ClassB", "class_id": 1 }]}

[github-actions]

🎨 Perfetto UI Builds

• 8025ca3 (2026-07-28 19:03 UTC): https://storage.googleapis.com/perfetto-ci-artifacts/gh-30389556845-1-ui/ui/index.html
• a2a9c4e (2026-07-28 21:04 UTC): https://storage.googleapis.com/perfetto-ci-artifacts/gh-30398621035-1-ui/ui/index.html

[LalitMaganti]

Sorry I'm not understanding the motivation for this patch. Is there a specific. Error etc you are working around?

There should not be any odr issue from have a C++ version of simplejsonpaser as a cc - if there was, we would have really big problems in a lot of places.

[MichaelFQuigley]

I encountered this error when trying to upload #6911:

ODR violation in target //src/trace_processor:trace_processor_shell_lib, multiple paths include //src/trace_processor/util:simple_json_parser:
  //src/trace_processor:trace_processor_shell_lib (via //src/trace_processor:trace_processor_shell_lib)
  //src/trace_processor/util/deobfuscation:deobfuscator (via //src/trace_processor/util/deobfuscation:deobfuscator)
Traceback (most recent call last):
  File "/usr/local/google/home/michaelquigley/perfetto/tools/gen_bazel", line 1289, in <module>
    sys.exit(main())
             ~~~~^^
  File "/usr/local/google/home/michaelquigley/perfetto/tools/gen_bazel", line 1263, in main
    contents = generate_build(desc, desc_win, desc_android, args.targets or
                              default_targets, extras)
  File "/usr/local/google/home/michaelquigley/perfetto/tools/gen_bazel", line 1201, in generate_build
    checker = gn_utils.ODRChecker(gn, target_name)
  File "/usr/local/google/home/michaelquigley/perfetto/tools/gn_utils.py", line 327, in __init__
    raise Exception('%d ODR violations detected. Build generation aborted' %
                    num_violations)
Exception: 1 ODR violations detected. Build generation aborted

i.e. SimpleJsonParser's impl was linked into both the //src/trace_processor/util/deobfuscation:deobfuscator and //src/trace_processor:lib libraries in #6911.

I'm a bit new to Bazel-specific nuances, so apologies if there is a more idiomatic way to handle this.

[LalitMaganti]

We should make this a perfetto_component as the correct way to solve that problem.

[MichaelFQuigley]

Thanks. Uploaded.