cppgc: Fix compilation when using Perfetto

The trace_event_common.h header file isn't used with Perfetto any
longer, so avoid adding a dependency to it from cppgc. Additionally
v8_tracing should be a public dependency so that any public headers
exposed from the target can also include tracing-related headers.

Bug: chromium:1006541
Change-Id: Ia3d48a8dad83df2ff3ea1ce36344dbb70ea83709
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2797278
Commit-Queue: Sami Kyöstilä <skyostil@chromium.org>
Commit-Queue: Dan Elphick <delphick@chromium.org>
Auto-Submit: Sami Kyöstilä <skyostil@chromium.org>
Reviewed-by: Dan Elphick <delphick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73748}

BUILD.gn

@@ -4984,12 +4984,6 @@ v8_source_set("cppgc_base") {
     "src/heap/cppgc/write-barrier.h",
   ]
 
-  if (cppgc_is_standalone) {
-    sources += [ "//base/trace_event/common/trace_event_common.h" ]
-  } else {
-    deps = [ ":v8_tracing" ]
-  }
-
   if (cppgc_enable_caged_heap) {
     sources += [
       "src/heap/cppgc/caged-heap-local-data.cc",
@@ -5009,6 +5003,12 @@ v8_source_set("cppgc_base") {
     ":v8_libbase",
     ":v8_libplatform",
   ]
+
+  if (cppgc_is_standalone && !v8_use_perfetto) {
+    sources += [ "//base/trace_event/common/trace_event_common.h" ]
+  } else {
+    public_deps += [ ":v8_tracing" ]
+  }
 }
 
 v8_source_set("cppgc_base_for_testing") {