Stop populating SystemProfileProto's ext renderer launch count field.

Stability.Counts2 has this info.

Bug: b/217949916
Change-Id: I41db52fa4ffb028c0aaa03116dd85d37cfeab462
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3557592
Reviewed-by: Robert Kaplow <[email protected]>
Auto-Submit: Caitlin Fischer <[email protected]>
Reviewed-by: Gabriel Charette <[email protected]>
Commit-Queue: Gabriel Charette <[email protected]>
Cr-Commit-Position: refs/heads/main@{#987235}
diff --git a/chrome/browser/prefs/browser_prefs.cc b/chrome/browser/prefs/browser_prefs.cc
index 772044d..433ea0d 100644
--- a/chrome/browser/prefs/browser_prefs.cc
+++ b/chrome/browser/prefs/browser_prefs.cc
@@ -737,6 +737,8 @@
 const char kStabilityLaunchCount[] =
     "user_experience_metrics.stability.launch_count";
 #endif
+const char kStabilityExtensionRendererLaunchCount[] =
+    "user_experience_metrics.stability.extension_renderer_launch_count";
 
 // Register local state used only for migration (clearing or moving to a new
 // key).
@@ -774,6 +776,7 @@
 #if !BUILDFLAG(IS_ANDROID)
   registry->RegisterIntegerPref(kStabilityLaunchCount, 0);
 #endif
+  registry->RegisterIntegerPref(kStabilityExtensionRendererLaunchCount, 0);
 }
 
 // Register prefs used only for migration (clearing or moving to a new key).
@@ -1616,6 +1619,7 @@
 #if !BUILDFLAG(IS_ANDROID)
   local_state->ClearPref(kStabilityLaunchCount);
 #endif
+  local_state->ClearPref(kStabilityExtensionRendererLaunchCount);
 
   // Please don't delete the following line. It is used by PRESUBMIT.py.
   // END_MIGRATE_OBSOLETE_LOCAL_STATE_PREFS