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

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

Index: chrome/browser/extensions/api/declarative_content/content_action.cc
diff --git a/chrome/browser/extensions/api/declarative_content/content_action.cc b/chrome/browser/extensions/api/declarative_content/content_action.cc
index 751f8d53383c946c633b1ef23066a414675e8554..3926a8b454da15235a59fa66abce6e8be658188a 100644
--- a/chrome/browser/extensions/api/declarative_content/content_action.cc
+++ b/chrome/browser/extensions/api/declarative_content/content_action.cc
@@ -94,6 +94,43 @@ class ShowPageAction : public ContentAction {
   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
@@ -113,6 +150,8 @@ struct ContentActionFactory {
   ContentActionFactory() {
     factory_methods[keys::kShowPageAction] =
         &ShowPageAction::Create;
+    factory_methods[keys::kRequestContentScript] =
+        &RequestContentScript::Create;
   }
 };