Declarative content scripts: Renderer-side: per-extension shared memory regions (lazily loaded)

extensions/renderer/user_script_set.cc

Index: extensions/renderer/user_script_set.cc
diff --git a/extensions/renderer/user_script_set.cc b/extensions/renderer/user_script_set.cc
index 5ab873955f026e98159d5567a4c111821d130c98..439e592d36a52eff350b36fc4654a3612f4e64b0 100644
--- a/extensions/renderer/user_script_set.cc
+++ b/extensions/renderer/user_script_set.cc
@@ -36,7 +36,6 @@ GURL GetDocumentUrlForFrame(blink::WebFrame* frame) {
 
 UserScriptSet::UserScriptSet(const ExtensionSet* extensions)
     : extensions_(extensions) {
-  content::RenderThread::Get()->AddObserver(this);
 }
 
 UserScriptSet::~UserScriptSet() {
@@ -79,22 +78,12 @@ void UserScriptSet::GetInjections(
   }
 }
 
-bool UserScriptSet::OnControlMessageReceived(
-    const IPC::Message& message) {
-  bool handled = true;
-  IPC_BEGIN_MESSAGE_MAP(UserScriptSet, message)
-    IPC_MESSAGE_HANDLER(ExtensionMsg_UpdateUserScripts, OnUpdateUserScripts)
-    IPC_MESSAGE_UNHANDLED(handled = false)
-  IPC_END_MESSAGE_MAP()
-  return handled;
-}
-
-void UserScriptSet::OnUpdateUserScripts(
+bool UserScriptSet::OnUpdateUserScripts(
     base::SharedMemoryHandle shared_memory,
     const std::set<std::string>& changed_extensions) {
   if (!base::SharedMemory::IsHandleValid(shared_memory)) {

[Devlin, 2014/07/29 17:11:57]

These can (and should) be moved to UserScriptSetManager - they are basically IPC
security checks, and should happen immediately upon receiving the message. 
(Which also means we can probably combine OnUpdateUserScripts and UpdatesScripts
into one method.)

[Mark Dittmer, 2014/07/29 22:01:13]

Done. Kept the OnUpdateUserScripts method name+signature.

     NOTREACHED() << "Bad scripts handle";
-    return;
+    return false;
   }
 
   for (std::set<std::string>::const_iterator iter = changed_extensions.begin();
@@ -102,15 +91,17 @@ void UserScriptSet::OnUpdateUserScripts(
        ++iter) {
     if (!Extension::IdIsValid(*iter)) {
       NOTREACHED() << "Invalid extension id: " << *iter;
-      return;
+      return false;
     }
   }
 
-  if (UpdateScripts(shared_memory)) {
-    FOR_EACH_OBSERVER(Observer,
-                      observers_,
-                      OnUserScriptsUpdated(changed_extensions, scripts_.get()));
-  }
+  if (!UpdateScripts(shared_memory))
+    return false;
+
+  FOR_EACH_OBSERVER(Observer,
+                    observers_,
+                    OnUserScriptsUpdated(changed_extensions, scripts_.get()));
+  return true;
 }
 
 bool UserScriptSet::UpdateScripts(