cppgc: Fix chromium build with v8_use_perfetto.

The dependency on v8_tracing supplies include paths &
dependencies on the tracing library when built with
v8_use_perfetto.

This is an attempt to fix the linux-perfetto-rel builder [1], which is
currently erroring:

FAILED: obj/v8/cppgc_base/sweeper.o
/b/s/w/ir/cache/goma/client/gomacc ../../third_party/llvm-build/Release+Asserts/bin/clang++ -MMD -MF...(too long)
In file included from ../../v8/src/heap/cppgc/sweeper.cc:24:
In file included from ../../v8/src/heap/cppgc/stats-collector.h:17:
In file included from ../../v8/src/heap/cppgc/trace-event.h:9:
In file included from ../../v8/src/tracing/trace-event.h:12:
gen/third_party/perfetto/protos/perfetto/trace/track_event/debug_annotation.pbzero.h:9:10: fatal error: 'perfetto/protozero/message.h' file not found
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

[1] https://ci.chromium.org/p/chromium/builders/ci/linux-perfetto-rel

Bug: chromium:1056170
Change-Id: Id5a382d472139f7abe5ead67ec6eed2f8395e6b5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2560257
Commit-Queue: Eric Seckler <eseckler@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71401}

BUILD.gn

@@ -4558,6 +4558,8 @@ v8_source_set("cppgc_base") {
 
   if (cppgc_is_standalone) {
     sources += [ "//base/trace_event/common/trace_event_common.h" ]
+  } else {
+    deps = [ ":v8_tracing" ]
   }
 
   if (cppgc_enable_caged_heap) {