Prepare declarativeContent API for new script injection feature. Added Javascript types and functio…

chrome/browser/extensions/api/declarative_content/content_action.cc

 // Copyright (c) 2012 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.
 
 #include "chrome/browser/extensions/api/declarative_content/content_action.h"
 
 #include <map>
 
 #include "base/lazy_instance.h"
 #include "base/strings/stringprintf.h"
@@ skipping 76 matching lines @@
             ->GetExtensionById(extension_id, ExtensionRegistry::EVERYTHING);
     if (!extension)
       return NULL;
     return ExtensionActionManager::Get(profile)->GetPageAction(*extension);
   }
   virtual ~ShowPageAction() {}
 
   DISALLOW_COPY_AND_ASSIGN(ShowPageAction);
 };
 
+// Action that injects a content script.
+class RequestContentScript : public ContentAction {
+ public:
+  RequestContentScript() {}
+
+  static scoped_refptr<ContentAction> Create(const Extension* extension,
+                                             const base::DictionaryValue* dict,
+                                             std::string* error,
+                                             bool* bad_message) {
+    return scoped_refptr<ContentAction>(new RequestContentScript);
+  }
+
+  // Implementation of ContentAction:
+  virtual Type GetType() const OVERRIDE {
+    return ACTION_REQUEST_CONTENT_SCRIPT;
+  }
+
+  virtual void Apply(const std::string& extension_id,
+                     const base::Time& extension_install_time,
+                     ApplyInfo* apply_info) const OVERRIDE {
+    // TODO(markdittmer): Invoke UserScriptMaster declarative script loader:
+    // load new user script.
+  }
+
+  virtual void Revert(const std::string& extension_id,
+                      const base::Time& extension_install_time,
+                      ApplyInfo* apply_info) const OVERRIDE {
+    // TODO(markdittmer): Invoke UserScriptMaster declarative script loader:
+    // unload user script.

[Jeffrey Yasskin, 2014/06/27 22:03:41]

It's impossible to unload a user script. These actions just need to be
un-revertable. You might need to add some logic so the Apply isn't called twice
for the same page.

[Mark Dittmer, 2014/06/30 11:50:35]

Perhaps this comment should say "stop future loads of user script".

I thought that UserScriptMaster can be told to reload its set of scripts. Why
can't this functionality be extended to remove a declarative script from the
list, then reload its set of scripts? It's not clear to me what happens when I
invoke removeRules(...) on a rule for script injection if it's impossible to ask
UserScriptMaster to stop loading the script.

+  }
+
+ private:
+  virtual ~RequestContentScript() {}
+
+  DISALLOW_COPY_AND_ASSIGN(RequestContentScript);
+};
+
 struct ContentActionFactory {
   // Factory methods for ContentAction instances. |extension| is the extension
   // for which the action is being created. |dict| contains the json dictionary
   // that describes the action. |error| is used to return error messages in case
   // the extension passed an action that was syntactically correct but
   // semantically incorrect. |bad_message| is set to true in case |dict| does
   // not confirm to the validated JSON specification.
   typedef scoped_refptr<ContentAction>(*FactoryMethod)(
       const Extension* /* extension */,
       const base::DictionaryValue* /* dict */,
       std::string* /* error */,
       bool* /* bad_message */);
   // Maps the name of a declarativeContent action type to the factory
   // function creating it.
   std::map<std::string, FactoryMethod> factory_methods;
 
   ContentActionFactory() {
     factory_methods[keys::kShowPageAction] =
         &ShowPageAction::Create;
+    factory_methods[keys::kRequestContentScript] =
+        &RequestContentScript::Create;
   }
 };
 
 base::LazyInstance<ContentActionFactory>::Leaky
     g_content_action_factory = LAZY_INSTANCE_INITIALIZER;
 
 }  // namespace
 
 //
 // ContentAction
@@ skipping 24 matching lines @@
       factory_method_iter = factory.factory_methods.find(instance_type);
   if (factory_method_iter != factory.factory_methods.end())
     return (*factory_method_iter->second)(
         extension, action_dict, error, bad_message);
 
   *error = base::StringPrintf(kInvalidInstanceTypeError, instance_type.c_str());
   return scoped_refptr<ContentAction>();
 }
 
 }  // namespace extensions