[PageLoadMetrics] Remove legacy IPC from Page Load Metrics.

chrome/common/chrome_features.cc

Index: chrome/common/chrome_features.cc
diff --git a/chrome/common/chrome_features.cc b/chrome/common/chrome_features.cc
index 9ebee9b91b32c5975cfc0bb8d2093648a0427db5..0b8904fabfeb350a93867968b2232c442b5647a0 100644
--- a/chrome/common/chrome_features.cc
+++ b/chrome/common/chrome_features.cc
@@ -378,10 +378,6 @@ const base::Feature kInstantTethering{"InstantTethering",
                                       base::FEATURE_DISABLED_BY_DEFAULT};
 #endif  // defined(OS_CHROMEOS)
 
-// Enables or disables Page Load Metrics using mojo IPC.
-const base::Feature kPageLoadMetricsMojofication{
-    "PLMMojofication", base::FEATURE_DISABLED_BY_DEFAULT};
-
 bool PrefServiceEnabled() {
   return base::FeatureList::IsEnabled(features::kPrefService) ||
 #if BUILDFLAG(ENABLE_PACKAGE_MASH_SERVICES)