Stop injection when injections are invalidated

extensions/renderer/user_script_injector.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/user_script_injector.h"
 
 #include <tuple>
 #include <vector>
 
 #include "base/lazy_instance.h"
@@ skipping 121 matching lines @@
 bool UserScriptInjector::IsUserGesture() const {
   return false;
 }
 
 bool UserScriptInjector::ExpectsResults() const {
   return false;
 }
 
 bool UserScriptInjector::ShouldInjectJs(
     UserScript::RunLocation run_location) const {
-  return script_ && script_->run_location() == run_location &&
+  CHECK(script_);
+  return script_->run_location() == run_location &&
          !script_->js_scripts().empty();
 }
 
 bool UserScriptInjector::ShouldInjectCss(
     UserScript::RunLocation run_location) const {
-  return script_ && run_location == UserScript::DOCUMENT_START &&
+  CHECK(script_);
+  return run_location == UserScript::DOCUMENT_START &&
          !script_->css_scripts().empty();
 }
 
 PermissionsData::AccessType UserScriptInjector::CanExecuteOnFrame(
     const InjectionHost* injection_host,
     blink::WebLocalFrame* web_frame,
     int tab_id) const {
-  // There is no harm in allowing the injection when the script is gone,
-  // because there is nothing to inject.
-  if (!script_)
-    return PermissionsData::ACCESS_ALLOWED;
+  CHECK(script_);
 
   if (script_->consumer_instance_type() ==
           UserScript::ConsumerInstanceType::WEBVIEW) {
     int routing_id = content::RenderView::FromWebView(web_frame->top()->view())
                         ->GetRoutingID();
 
     RoutingInfoKey key(routing_id, script_->id());
 
     RoutingInfoMap& map = g_routing_info_map.Get();
     auto iter = map.find(key);
@@ skipping 21 matching lines @@
 
   return injection_host->CanExecuteOnFrame(
       effective_document_url,
       content::RenderFrame::FromWebFrame(web_frame),
       tab_id,
       is_declarative_);
 }
 
 std::vector<blink::WebScriptSource> UserScriptInjector::GetJsSources(
     UserScript::RunLocation run_location) const {
-  std::vector<blink::WebScriptSource> sources;
-  if (!script_)
-    return sources;
-
+  CHECK(script_);
   DCHECK_EQ(script_->run_location(), run_location);
 
   const UserScript::FileList& js_scripts = script_->js_scripts();
 
+  std::vector<blink::WebScriptSource> sources;
   for (UserScript::FileList::const_iterator iter = js_scripts.begin();
        iter != js_scripts.end();
        ++iter) {
     std::string content = iter->GetContent().as_string();
 
     // We add this dumb function wrapper for user scripts to emulate what
     // Greasemonkey does.
     if (script_->emulate_greasemonkey()) {
       content.insert(0, kUserScriptHead);
       content += kUserScriptTail;
     }
     sources.push_back(blink::WebScriptSource(
         blink::WebString::fromUTF8(content), iter->url()));
   }
 
   // Emulate Greasemonkey API for scripts that were converted to extension
   // user scripts.
   if (script_->emulate_greasemonkey())
     sources.insert(sources.begin(), g_greasemonkey_api.Get().GetSource());
 
   return sources;
 }
 
 std::vector<std::string> UserScriptInjector::GetCssSources(
     UserScript::RunLocation run_location) const {
   DCHECK_EQ(UserScript::DOCUMENT_START, run_location);
+  CHECK(script_);
 
   std::vector<std::string> sources;
-  if (!script_)
-    return sources;
-
   const UserScript::FileList& css_scripts = script_->css_scripts();
   for (UserScript::FileList::const_iterator iter = css_scripts.begin();
        iter != css_scripts.end();
        ++iter) {
     sources.push_back(iter->GetContent().as_string());
   }
   return sources;
 }
 
 void UserScriptInjector::GetRunInfo(
     ScriptsRunInfo* scripts_run_info,
     UserScript::RunLocation run_location) const {
-  if (!script_)
-    return;
+  CHECK(script_);
 
   if (ShouldInjectJs(run_location)) {
     const UserScript::FileList& js_scripts = script_->js_scripts();
     scripts_run_info->num_js += js_scripts.size();
     for (UserScript::FileList::const_iterator iter = js_scripts.begin();
          iter != js_scripts.end();
          ++iter) {
       scripts_run_info->executing_scripts[host_id_.id()].insert(
           iter->url().path());
     }
   }
 
   if (ShouldInjectCss(run_location))
     scripts_run_info->num_css += script_->css_scripts().size();
 }
 
 void UserScriptInjector::OnInjectionComplete(
     std::unique_ptr<base::Value> execution_result,
     UserScript::RunLocation run_location,
     content::RenderFrame* render_frame) {}
 
 void UserScriptInjector::OnWillNotInject(InjectFailureReason reason,
                                          content::RenderFrame* render_frame) {
 }
 
 }  // namespace extensions