Refactoring: de-couple Extensions from "script injection System" [render side]:2

chrome/browser/extensions/user_script_loader.cc

 // 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.
 
 #include "chrome/browser/extensions/user_script_loader.h"
 
 #include <set>
 #include <string>
 
 #include "base/bind.h"
@@ skipping 423 matching lines @@
     // though it removes the possibility that freeing the shared memory block
     // would open up enough FDs for long enough for a retry to succeed.
 
     // Pretend the extension change didn't happen.
     return;
   }
 
   // We've got scripts ready to go.
   shared_memory_.reset(shared_memory.release());
 
+  // If user scripts are comming from a <webview>, will only notify the
+  // RenderProcessHost of that <webview>; otherwise will notify all of the
+  // RenderProcessHosts.
+  bool is_web_view = false;
+  int render_process_id = -1;
+  const UserScriptList* scripts = user_scripts.get();

[Devlin, 2015/02/23 20:15:00]

Why cache this, isntead of just using user_scripts?

[Xi Han, 2015/02/24 16:19:54]

Each of them is fine to me. Update.

+  if (scripts && !scripts->empty() &&
+      (*scripts)[0].consumer_instance_type() ==
+          UserScript::ConsumerInstanceType::WEBVIEW) {
+    DCHECK(scripts->size() == 1);

[Devlin, 2015/02/23 20:15:00]

nit: DCHECK_EQ(1u, scripts->size());

[Xi Han, 2015/02/24 16:19:54]

Done.

+    is_web_view = true;
+    render_process_id = (*scripts)[0].routing_info().render_process_id;
+  }
+
   for (content::RenderProcessHost::iterator i(

[Devlin, 2015/02/23 20:15:00]

I think this is clearer as:
if (is_web_view) {
  RenderProcessHost* host = RenderProcessHost::FromId(id);
  if (host)
    SendUpdate(host...);
} else {
  for (content::RPH::iterator i(content::RPH::AllHostsIterator();
       !i.IsAtEnd(); i.Advance()) {
    SendUpdate(i.GetCurrentValue()...);
  }
}

This also means that you can actually replace |is_web_view| the content of the
if statement on line 450-452.

[Fady Samuel, 2015/02/23 20:16:57]

Does this mean that there is one UserScriptLoader per <webview>?

[Xi Han, 2015/02/24 16:19:54]

Great idea, the logic is much clear now.

[Xi Han, 2015/02/24 16:19:54]

We still have UserScriptLoader per hostID, user scripts from the same hostID
(may have different webviews and tabs) will be saved in the same shared memory
region. The changes here is: if we find out a user script is from webview, we
only send notification from the specified RenderViewHost of that webview, rather
than all the RenderViewHost.

            content::RenderProcessHost::AllHostsIterator());
        !i.IsAtEnd();
        i.Advance()) {
+    if (is_web_view && i.GetCurrentValue()->GetID() != render_process_id) {
+        continue;
+      }
     SendUpdate(i.GetCurrentValue(), shared_memory_.get(), changed_hosts_);
+    if (is_web_view)
+      break;
   }
   changed_hosts_.clear();
 
   content::NotificationService::current()->Notify(
       extensions::NOTIFICATION_USER_SCRIPTS_UPDATED,
       content::Source<Profile>(profile_),
       content::Details<base::SharedMemory>(shared_memory_.get()));
 }
 
 void UserScriptLoader::SendUpdate(content::RenderProcessHost* process,
@@ skipping 24 matching lines @@
   for (const HostID& id : changed_hosts)
     changed_ids_set.insert(id.id());
 
   if (base::SharedMemory::IsHandleValid(handle_for_process)) {
     process->Send(new ExtensionMsg_UpdateUserScripts(
         handle_for_process, host_id().id(), changed_ids_set));
   }
 }
 
 }  // namespace extensions