Refactoring: de-couple Extensions from "script injection System" [render side]:3

extensions/renderer/script_injection_manager.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 "extensions/renderer/script_injection_manager.h"
 
 #include "base/auto_reset.h"
 #include "base/bind.h"
 #include "base/memory/weak_ptr.h"
 #include "base/values.h"
@@ skipping 35 matching lines @@
     case UserScript::UNDEFINED:
     case UserScript::RUN_DEFERRED:
     case UserScript::BROWSER_DRIVEN:
     case UserScript::RUN_LOCATION_LAST:
       break;
   }
   NOTREACHED();
   return UserScript::RUN_LOCATION_LAST;
 }
 
-
-// TODO(hanxi): let ScriptInjection own an InjectionHost to avoid constructing
-// an ExtensionInjectionHost many times.
-// Note: the ScriptInjection should be able to know when the backing extension
-// is removed.
-scoped_ptr<ExtensionInjectionHost> GetExtensionInjectionHost(
-    const std::string& extension_id, const ExtensionSet* extensions) {
-  const Extension* extension = extensions->GetByID(extension_id);
-  if (!extension)
-    return scoped_ptr<ExtensionInjectionHost>();
-  return scoped_ptr<ExtensionInjectionHost>(
-      new ExtensionInjectionHost(extension));
-}
-
 }  // namespace
 
 class ScriptInjectionManager::RVOHelper : public content::RenderViewObserver {
  public:
   RVOHelper(content::RenderView* render_view, ScriptInjectionManager* manager);
   ~RVOHelper() override;
 
  private:
   // RenderViewObserver implementation.
   bool OnMessageReceived(const IPC::Message& message) override;
@@ skipping 169 matching lines @@
 }
 
 ScriptInjectionManager::~ScriptInjectionManager() {
 }
 
 void ScriptInjectionManager::OnRenderViewCreated(
     content::RenderView* render_view) {
   rvo_helpers_.push_back(new RVOHelper(render_view, this));
 }
 
+void ScriptInjectionManager::OnExtensionUnloaded(

[Devlin, 2015/02/20 22:39:13]

Unfortunately, for the time being, if a script blocks, we run a nested message
loop. This basically means it can be unsafe to erase injections like this. 
Instead, we should check if |injecting_scripts_| is true, and, if so, add the id
to |invalidated_while_injecting_|.

[Xi Han, 2015/02/23 16:14:59]

Thanks for pointing out this. Add a check for |injecting_scripts_| and insert
the |extension_id| to |invalidated_while_injecting_|.

+    const std::string& extension_id) {
+  for(auto iter = pending_injections_.begin();
+      iter != pending_injections_.end();) {
+    if ((*iter)->host_id().id() == extension_id) {
+      (*iter)->set_injection_host(nullptr);
+      iter = pending_injections_.erase(iter);
+    }
+    else
+      ++iter;
+  }
+}
+
 void ScriptInjectionManager::OnUserScriptsUpdated(
     const std::set<std::string>& changed_extensions,
     const std::vector<UserScript*>& scripts) {
   for (ScopedVector<ScriptInjection>::iterator iter =
            pending_injections_.begin();
        iter != pending_injections_.end();) {
     if (changed_extensions.count((*iter)->host_id().id()) > 0)
       iter = pending_injections_.erase(iter);
     else
       ++iter;
@@ skipping 116 matching lines @@
       &frame_injections, frame, tab_id, run_location);
 
   ScriptsRunInfo scripts_run_info;
   for (ScopedVector<ScriptInjection>::iterator iter = frame_injections.begin();
        iter != frame_injections.end();) {
     // If a blocking script was injected, there is potentially a possibility
     // that the frame has been invalidated in the time since. Check.
     if (!IsFrameValid(frame))
       break;
 
-    const std::string& extension_id = (*iter)->host_id().id();
-    scoped_ptr<ExtensionInjectionHost> extension_injection_host =
-        GetExtensionInjectionHost(extension_id, extensions_);
-    // Try to inject the script if the extension is not "dirty" (invalidated by
-    // an update). If the injection does not finish (i.e., it is waiting for
-    // permission), add it to the list of pending injections.
-    if (invalidated_while_injecting_.count(extension_id) == 0 &&
+    // Try to inject the script if the injection host is not "dirty"
+    // (invalidated by an update). If the injection does not finish
+    // (i.e., it is waiting for permission), add it to the list of pending
+    // injections.
+    if (invalidated_while_injecting_.count((*iter)->host_id().id()) == 0 &&
         !(*iter)->TryToInject(run_location,
-                              extension_injection_host.get(),
                               &scripts_run_info)) {
       pending_injections_.insert(pending_injections_.begin(), *iter);
       iter = frame_injections.weak_erase(iter);
     } else {
       ++iter;
     }
   }
 
   if (IsFrameValid(frame))
     scripts_run_info.LogRun(frame, run_location);
@@ skipping 12 matching lines @@
   if (!main_frame) {
     render_view->Send(
         new ExtensionHostMsg_ExecuteCodeFinished(render_view->GetRoutingID(),
                                                  params.request_id,
                                                  "No main frame",
                                                  GURL(std::string()),
                                                  base::ListValue()));
     return;
   }
 
+  scoped_ptr<const ExtensionInjectionHost> extension_injection_host =
+      ExtensionInjectionHost::Create(params.extension_id, extensions_);
+
+  if (!extension_injection_host.get())

[Devlin, 2015/02/20 22:39:13]

remove the get

[Xi Han, 2015/02/23 16:14:59]

Done.

+    return;
+
   scoped_ptr<ScriptInjection> injection(new ScriptInjection(
       scoped_ptr<ScriptInjector>(
           new ProgrammaticScriptInjector(params, main_frame)),
       main_frame,
-      HostID(HostID::EXTENSIONS, params.extension_id),
+      extension_injection_host.Pass(),
       params.is_web_view ? UserScript::ConsumerInstanceType::WEBVIEW
                          : UserScript::ConsumerInstanceType::TAB,
       static_cast<UserScript::RunLocation>(params.run_at),
       ExtensionHelper::Get(render_view)->tab_id()));
 
   ScriptsRunInfo scripts_run_info;
   FrameStatusMap::const_iterator iter = frame_statuses_.find(main_frame);
 
-  scoped_ptr<ExtensionInjectionHost> extension_injection_host =
-      GetExtensionInjectionHost(injection->host_id().id(), extensions_);
-
   if (!injection->TryToInject(
           iter == frame_statuses_.end() ? UserScript::UNDEFINED : iter->second,
-          extension_injection_host.get(),
           &scripts_run_info)) {
     pending_injections_.push_back(injection.release());
   }
 }
 
 void ScriptInjectionManager::HandleExecuteDeclarativeScript(
     blink::WebFrame* web_frame,
     int tab_id,
     const ExtensionId& extension_id,
     int script_id,
     const GURL& url) {
-  scoped_ptr<ExtensionInjectionHost> extension_injection_host =
-      GetExtensionInjectionHost(extension_id, extensions_);
-  const Extension* extension = extensions_->GetByID(extension_id);
   // TODO(dcheng): This function signature should really be a WebLocalFrame,
   // rather than trying to coerce it here.
   scoped_ptr<ScriptInjection> injection =
       user_script_set_manager_->GetInjectionForDeclarativeScript(
           script_id,
           web_frame->toWebLocalFrame(),
           tab_id,
           url,
-          extension);
+          extension_id);
   if (injection.get()) {
     ScriptsRunInfo scripts_run_info;
     // TODO(markdittmer): Use return value of TryToInject for error handling.
     injection->TryToInject(UserScript::BROWSER_DRIVEN,
-                           extension_injection_host.get(),
                            &scripts_run_info);
     scripts_run_info.LogRun(web_frame, UserScript::BROWSER_DRIVEN);
   }
 }
 
 void ScriptInjectionManager::HandlePermitScriptInjection(int64 request_id) {
   ScopedVector<ScriptInjection>::iterator iter =
       pending_injections_.begin();
   for (; iter != pending_injections_.end(); ++iter) {
-    if ((*iter)->request_id() == request_id)
+    if ((*iter)->request_id() == request_id &&
+        (*iter)->host_id().type() == HostID::EXTENSIONS)

[Devlin, 2015/02/20 22:39:13]

Is there any time when the script injection could have the request id, but not
be an extension?  If not, can we DCHECK this?

[Xi Han, 2015/02/23 16:14:59]

DCHECK makes more sense, updated.

       break;
   }
   if (iter == pending_injections_.end())
     return;
 
   // At this point, because the request is present in pending_injections_, we
   // know that this is the same page that issued the request (otherwise,
   // RVOHelper's DidStartProvisionalLoad callback would have caused it to be
   // cleared out).
 
   scoped_ptr<ScriptInjection> injection(*iter);
   pending_injections_.weak_erase(iter);
 
   ScriptsRunInfo scripts_run_info;
-  scoped_ptr<ExtensionInjectionHost> extension_injection_host =
-      GetExtensionInjectionHost(injection->host_id().id(), extensions_);
-  if (injection->OnPermissionGranted(extension_injection_host.get(),
-                                     &scripts_run_info)) {
+  if (injection->OnPermissionGranted(&scripts_run_info)) {
     scripts_run_info.LogRun(injection->web_frame(), UserScript::RUN_DEFERRED);
   }
 }
 
 }  // namespace extensions