Prevent duplicate content script injection defined in manifest.json (reland)

extensions/renderer/programmatic_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/programmatic_script_injector.h"
 
 #include <utility>
 #include <vector>
 
 #include "base/values.h"
 #include "content/public/common/url_constants.h"
 #include "content/public/renderer/render_frame.h"
 #include "extensions/common/error_utils.h"
 #include "extensions/common/extension_messages.h"
 #include "extensions/common/manifest_constants.h"
 #include "extensions/common/permissions/api_permission.h"
 #include "extensions/common/permissions/permissions_data.h"
 #include "extensions/renderer/injection_host.h"
 #include "extensions/renderer/renderer_extension_registry.h"
 #include "extensions/renderer/script_context.h"
+#include "extensions/renderer/scripts_run_info.h"
 #include "third_party/WebKit/public/platform/WebString.h"
 #include "third_party/WebKit/public/web/WebDocument.h"
 #include "third_party/WebKit/public/web/WebLocalFrame.h"
 #include "third_party/WebKit/public/web/WebScriptSource.h"
 
 namespace extensions {
 
 ProgrammaticScriptInjector::ProgrammaticScriptInjector(
     const ExtensionMsg_ExecuteCode_Params& params,
     content::RenderFrame* render_frame)
@@ skipping 21 matching lines @@
 
 bool ProgrammaticScriptInjector::IsUserGesture() const {
   return params_->user_gesture;
 }
 
 bool ProgrammaticScriptInjector::ExpectsResults() const {
   return params_->wants_result;
 }
 
 bool ProgrammaticScriptInjector::ShouldInjectJs(
-    UserScript::RunLocation run_location) const {
-  return GetRunLocation() == run_location && params_->is_javascript;
+    UserScript::RunLocation run_location,
+    ScriptsRunInfo* scripts_run_info) const {
+  return GetRunLocation() == run_location && params_->is_javascript &&
+         !scripts_run_info->injected_scripts.empty();

[Devlin, 2016/08/03 23:34:44]

This line means that we only inject js if there's already been a js injection,
doesn't it?

 }
 
 bool ProgrammaticScriptInjector::ShouldInjectCss(
-    UserScript::RunLocation run_location) const {
-  return GetRunLocation() == run_location && !params_->is_javascript;
+    UserScript::RunLocation run_location,
+    ScriptsRunInfo* scripts_run_info) const {
+  return GetRunLocation() == run_location && !params_->is_javascript &&
+         !scripts_run_info->injected_scripts.empty();
 }
 
 PermissionsData::AccessType ProgrammaticScriptInjector::CanExecuteOnFrame(
     const InjectionHost* injection_host,
     blink::WebLocalFrame* frame,
     int tab_id) const {
   GURL effective_document_url = ScriptContext::GetEffectiveDocumentURL(
       frame, frame->document().url(), params_->match_about_blank);
   if (params_->is_web_view) {
     if (frame->parent()) {
       // This is a subframe inside <webview>, so allow it.
       return PermissionsData::ACCESS_ALLOWED;
     }
 
     return effective_document_url == params_->webview_src
                ? PermissionsData::ACCESS_ALLOWED
                : PermissionsData::ACCESS_DENIED;
   }
   DCHECK_EQ(injection_host->id().type(), HostID::EXTENSIONS);
 
   return injection_host->CanExecuteOnFrame(
       effective_document_url,
       content::RenderFrame::FromWebFrame(frame),
       tab_id,
       true /* is_declarative */);
 }
 
 std::vector<blink::WebScriptSource> ProgrammaticScriptInjector::GetJsSources(
-    UserScript::RunLocation run_location) const {
+    UserScript::RunLocation run_location,
+    ScriptsRunInfo* scripts_run_info) const {
   DCHECK_EQ(GetRunLocation(), run_location);
   DCHECK(params_->is_javascript);
 
   return std::vector<blink::WebScriptSource>(
       1,
       blink::WebScriptSource(
           blink::WebString::fromUTF8(params_->code), params_->file_url));
 }
 
 std::vector<std::string> ProgrammaticScriptInjector::GetCssSources(
-    UserScript::RunLocation run_location) const {
+    UserScript::RunLocation run_location,
+    ScriptsRunInfo* scripts_run_info) const {
   DCHECK_EQ(GetRunLocation(), run_location);
   DCHECK(!params_->is_javascript);
 
   return std::vector<std::string>(1, params_->code);
 }
 
 void ProgrammaticScriptInjector::GetRunInfo(
     ScriptsRunInfo* scripts_run_info,
     UserScript::RunLocation run_location) const {
 }
@@ skipping 57 matching lines @@
   // frame deletions so nothing is left hanging).
   if (render_frame) {
     render_frame->Send(
         new ExtensionHostMsg_ExecuteCodeFinished(
             render_frame->GetRoutingID(), params_->request_id,
             error, url_, results_));
   }
 }
 
 }  // namespace extensions