gn: Allow reading cppgc_enable_object_names from Blink

The flag is required to allow passing in more debug information when
necessary.

Change-Id: I34e407ba57786c242aac8b6f6af258969de43efd
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3468894Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79126}

BUILD.gn

@@ -278,9 +278,6 @@ declare_args() {
   # ARM64.
   v8_control_flow_integrity = false
 
-  # Enable object names in cppgc for debug purposes.
-  cppgc_enable_object_names = false
-
   # Enable heap reservation of size 4GB. Only possible for 64bit archs.
   cppgc_enable_caged_heap =
       v8_current_cpu == "x64" || v8_current_cpu == "arm64" ||

gni/v8.gni

@@ -86,6 +86,9 @@ declare_args() {
 
   cppgc_is_standalone = false
 
+  # Enable object names in cppgc for debug purposes.
+  cppgc_enable_object_names = false
+
   # Enable young generation in cppgc.
   cppgc_enable_young_generation = false