Add HeapCompaction FeatureList flag

content/public/common/content_features.cc

Index: content/public/common/content_features.cc
diff --git a/content/public/common/content_features.cc b/content/public/common/content_features.cc
index a1fa2e8cad27e3f6847ccd840a3f84c9682932ff..f2ef3688103cf78d685bf175a2587d1e418e815b 100644
--- a/content/public/common/content_features.cc
+++ b/content/public/common/content_features.cc
@@ -101,6 +101,10 @@ const base::Feature kGenericSensor{"GenericSensor",
 const base::Feature kGuestViewCrossProcessFrames{
     "GuestViewCrossProcessFrames", base::FEATURE_DISABLED_BY_DEFAULT};
 
+// Enables BlinkGC heap compaction.
+const base::Feature kHeapCompaction{"HeapCompaction",
+                                     base::FEATURE_DISABLED_BY_DEFAULT};
+
 // Enables lazily parsing css properties for performance.
 const base::Feature kLazyParseCSS{"LazyParseCSS",
                                   base::FEATURE_DISABLED_BY_DEFAULT};