[Extensions] Add renderer-side logic to short circuit activity logging

extensions/renderer/script_injection_manager.h

Index: extensions/renderer/script_injection_manager.h
diff --git a/extensions/renderer/script_injection_manager.h b/extensions/renderer/script_injection_manager.h
index 814a8fee4526e7a4e7e1871fa211f7ea6dbed52a..83f4ebc085dba8b9d6a3e23770447f402744e9d4 100644
--- a/extensions/renderer/script_injection_manager.h
+++ b/extensions/renderer/script_injection_manager.h
@@ -44,6 +44,10 @@ class ScriptInjectionManager : public UserScriptSetManager::Observer {
   // Removes pending injections of the unloaded extension.
   void OnExtensionUnloaded(const std::string& extension_id);
 
+  void set_activity_logging_enabled(bool enabled) {
+    activity_logging_enabled_ = enabled;
+  }
+
  private:
   // A RenderFrameObserver implementation which watches the various render
   // frames in order to notify the ScriptInjectionManager of different
@@ -115,6 +119,9 @@ class ScriptInjectionManager : public UserScriptSetManager::Observer {
   // Running injections which are waiting for async callbacks from blink.
   ScriptInjectionVector running_injections_;
 
+  // Whether or not dom activity should be logged for scripts injected.
+  bool activity_logging_enabled_;
+
   ScopedObserver<UserScriptSetManager, UserScriptSetManager::Observer>
       user_script_set_manager_observer_;