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(
+scoped_ptr<const 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>(
+    return scoped_ptr<const ExtensionInjectionHost>();
+  return scoped_ptr<const ExtensionInjectionHost>(
       new ExtensionInjectionHost(extension));
 }
 
 }  // namespace
 
 class ScriptInjectionManager::RVOHelper : public content::RenderViewObserver {
  public:
   RVOHelper(content::RenderView* render_view, ScriptInjectionManager* manager);
   ~RVOHelper() override;
 
@@ skipping 308 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(),
+                              (*iter)->GetInjectionHost(),

[Devlin, 2015/02/17 18:56:52]

This is a bit silly - the ScriptInjection owns the injection host; why does it
need to be passed in?

[Xi Han, 2015/02/18 21:11:46]

Removed, and also updated some other functions that take InjectionHost* as input
parameters.

                               &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 =
+      GetExtensionInjectionHost(params.extension_id, extensions_);
+
+  if (!extension_injection_host)
+    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(),
+          injection->GetInjectionHost(),
           &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 =
+  scoped_ptr<const 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_injection_host.get());
   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)
       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 =
+  scoped_ptr<const ExtensionInjectionHost> extension_injection_host =
       GetExtensionInjectionHost(injection->host_id().id(), extensions_);
   if (injection->OnPermissionGranted(extension_injection_host.get(),
                                      &scripts_run_info)) {
     scripts_run_info.LogRun(injection->web_frame(), UserScript::RUN_DEFERRED);
   }
 }
 
 }  // namespace extensions