Introduce ClassicPendingScript::is_external_ explicitly

third_party/WebKit/Source/core/dom/ClassicPendingScript.cpp

 // Copyright 2017 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 "core/dom/ClassicPendingScript.h"
 
 #include "bindings/core/v8/ScriptSourceCode.h"
 #include "bindings/core/v8/ScriptState.h"
 #include "bindings/core/v8/ScriptStreamer.h"
 #include "bindings/core/v8/V8BindingForCore.h"
 #include "core/dom/Document.h"
 #include "core/dom/TaskRunnerHelper.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/SubresourceIntegrity.h"
 #include "platform/loader/fetch/MemoryCache.h"
 
 namespace blink {
 
 ClassicPendingScript* ClassicPendingScript::Create(ScriptElementBase* element,
                                                    ScriptResource* resource) {
+  CHECK(resource);
   return new ClassicPendingScript(element, resource, TextPosition());
 }
 
 ClassicPendingScript* ClassicPendingScript::Create(
     ScriptElementBase* element,
     const TextPosition& starting_position) {
   return new ClassicPendingScript(element, nullptr, starting_position);
 }
 
 ClassicPendingScript::ClassicPendingScript(
     ScriptElementBase* element,
     ScriptResource* resource,
     const TextPosition& starting_position)
-    : PendingScript(element, starting_position), integrity_failure_(false) {
+    : PendingScript(element, starting_position),
+      is_external_(resource),
+      integrity_failure_(false) {
+  CHECK(GetElement());
+  SetResource(resource);
   CheckState();
-  SetResource(resource);
   MemoryCoordinator::Instance().RegisterClient(this);
 }
 
 ClassicPendingScript::~ClassicPendingScript() {}
 
 NOINLINE void ClassicPendingScript::CheckState() const {
   // TODO(hiroshige): Turn these CHECK()s into DCHECK() before going to beta.
   CHECK(!prefinalizer_called_);
   CHECK(GetElement());
+  CHECK_EQ(is_external_, !!GetResource());
   CHECK(GetResource() || !streamer_);
   CHECK(!streamer_ || streamer_->GetResource() == GetResource());
 }
 
 void ClassicPendingScript::Prefinalize() {
   // TODO(hiroshige): Consider moving this to ScriptStreamer's prefinalizer.
   // https://crbug.com/715309
   if (streamer_)
     streamer_->Cancel();
   prefinalizer_called_ = true;
@@ skipping 106 matching lines @@
   ResourceOwner<ScriptResource>::Trace(visitor);
   MemoryCoordinatorClient::Trace(visitor);
   PendingScript::Trace(visitor);
 }
 
 ClassicScript* ClassicPendingScript::GetSource(const KURL& document_url,
                                                bool& error_occurred) const {
   CheckState();
 
   error_occurred = this->ErrorOccurred();
-  if (GetResource()) {
+  if (is_external_) {

[sof, 2017/04/29 15:01:10]

Why is this (and all the other is_external_ checks added here) 'better' than the
GetResource() checks previously there?

     DCHECK(GetResource()->IsLoaded());
     if (streamer_ && !streamer_->StreamingSuppressed())
       return ClassicScript::Create(ScriptSourceCode(streamer_, GetResource()));
     return ClassicScript::Create(ScriptSourceCode(GetResource()));
   }
 
   return ClassicScript::Create(ScriptSourceCode(
       GetElement()->TextContent(), document_url, StartingPosition()));
 }
 
 void ClassicPendingScript::SetStreamer(ScriptStreamer* streamer) {
   DCHECK(!streamer_);
   DCHECK(!IsWatchingForLoad());
   streamer_ = streamer;
   CheckState();
 }
 
 bool ClassicPendingScript::IsReady() const {
   CheckState();
-  if (GetResource()) {
+  if (is_external_) {
     return GetResource()->IsLoaded() && (!streamer_ || streamer_->IsFinished());
   }
 
   return true;
 }
 
 bool ClassicPendingScript::ErrorOccurred() const {
   CheckState();
-  if (GetResource())
+  if (is_external_)
     return GetResource()->ErrorOccurred() || integrity_failure_;
 
   return false;
 }
 
 void ClassicPendingScript::OnPurgeMemory() {
   CheckState();
   if (!streamer_)
     return;
   streamer_->Cancel();
@@ skipping 21 matching lines @@
 
 KURL ClassicPendingScript::UrlForClassicScript() const {
   return GetResource()->Url();
 }
 
 void ClassicPendingScript::RemoveFromMemoryCache() {
   GetMemoryCache()->Remove(GetResource());
 }
 
 }  // namespace blink