Stop injection when injections are invalidated

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 aaad2c9d58f5edaa5fa145cad378bdd6b60daed2..d2283f07a3ae57223d80b9e1c70caabbe8dd3a3e 100644
--- a/extensions/renderer/script_injection_manager.h
+++ b/extensions/renderer/script_injection_manager.h
@@ -53,6 +53,7 @@ class ScriptInjectionManager : public UserScriptSetManager::Observer {
   // frames in order to notify the ScriptInjectionManager of different
   // document load states and IPCs.
   class RFOHelper;
+  class ScriptInjectionWatcher;
 
   using FrameStatusMap =
       std::map<content::RenderFrame*, UserScript::RunLocation>;
@@ -119,6 +120,10 @@ class ScriptInjectionManager : public UserScriptSetManager::Observer {
   // Running injections which are waiting for async callbacks from blink.
   ScriptInjectionVector running_injections_;
 
+  // Tracks injections that are about to be injected. Injections are added
+  // right before injection, and removed immediately after.
+  std::vector<ScriptInjectionWatcher*> injection_watchers_;
+
   // Whether or not dom activity should be logged for scripts injected.
   bool activity_logging_enabled_ = false;