Don't report a keepalive count for persistent pages.

extensions/browser/process_manager.cc

Index: extensions/browser/process_manager.cc
diff --git a/extensions/browser/process_manager.cc b/extensions/browser/process_manager.cc
index 3e4d1062185a292b968eb1f1497f6a63a93c7815..dc3b5e71266cc0a0b0c4ed56d36d244f6ed572b3 100644
--- a/extensions/browser/process_manager.cc
+++ b/extensions/browser/process_manager.cc
@@ -472,7 +472,7 @@ const Extension* ProcessManager::GetExtensionForWebContents(
 
 int ProcessManager::GetLazyKeepaliveCount(const Extension* extension) {
   if (!BackgroundInfo::HasLazyBackgroundPage(extension))
-    return 0;
+    return -1;
 
   return background_page_data_[extension->id()].lazy_keepalive_count;
 }