Stop injection when injections are invalidated

extensions/renderer/script_injection.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef EXTENSIONS_RENDERER_SCRIPT_INJECTION_H_
 #define EXTENSIONS_RENDERER_SCRIPT_INJECTION_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 23 matching lines @@
 namespace extensions {
 struct ScriptsRunInfo;
 
 // A script wrapper which is aware of whether or not it is allowed to execute,
 // and contains the implementation to do so.
 class ScriptInjection {
  public:
   enum InjectionResult {
     INJECTION_FINISHED,
     INJECTION_BLOCKED,
+    INJECTION_CANCELED,
     INJECTION_WAITING
   };
 
   using CompletionCallback = base::Callback<void(ScriptInjection*)>;
 
   // Return the id of the injection host associated with the given world.
   static std::string GetHostIdForIsolatedWorld(int world_id);
 
   // Remove the isolated world associated with the given injection host.
   static void RemoveIsolatedWorld(const std::string& host_id);
@@ skipping 34 matching lines @@
   int64_t request_id() const { return request_id_; }
 
  private:
   class FrameWatcher;
 
   // Sends a message to the browser to request permission to inject.
   void RequestPermissionFromBrowser();
 
   // Injects the script. Returns INJECTION_FINISHED if injection has finished,
   // otherwise INJECTION_BLOCKED.
+  // The caller must not destruct this ScriptInjection instance during the call.
+  // Similarly, this instance must not delete itself during the call.
   InjectionResult Inject(ScriptsRunInfo* scripts_run_info);
 
   // Inject any JS scripts into the frame for the injection.
   void InjectJs();
 
   // Called when JS injection for the given frame has been completed.
   void OnJsInjectionCompleted(
       const blink::WebVector<v8::Local<v8::Value> >& results);
 
   // Inject any CSS source into the frame for the injection.
@@ skipping 38 matching lines @@
   std::unique_ptr<FrameWatcher> frame_watcher_;
 
   base::WeakPtrFactory<ScriptInjection> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ScriptInjection);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_RENDERER_SCRIPT_INJECTION_H_