[Oilpan] De-oilpanize ScopedPageLoadDeferrer.

ScopedPageLoadDeferrer is an RAII-like class that does some work when it is
constructed and destructed, just like other ScopedXXX classes.

It was oilpanized in the past, and a new method, dispose(), was added to
do clean-ups that had been done in the destructor. However, a few stack-
allocated usages were overlooked in that change.

Garbage-collected objects shouldn't be allocated on the stack. So, stack-
allocated usages should be converted to heap-allocated, with dispose() calls
added in every single place where the object can go out of scope.

However, I find this conversion too cumbersome and less C++-idiomatic.

Therefore, this patch instead de-oilpanizes ScopedPageLoadDeferrer. The only
reference to will-be-heap-managed class in ScopedPageLoadDeferrer is
RefPtr<LocalFrame>, so it is safe to convert it to RefPtrWillBePersistent.

I think this patch makes the code cleaner overall.

BUG=486590
R=haraken@chromium.org, oilpan-reviews@chromium.org, sigbjornf@opera.com

Review URL: https://codereview.chromium.org/1316663004

git-svn-id: svn://svn.chromium.org/blink/trunk@201630 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/core/page/ScopedPageLoadDeferrer.cpp

@@ -31,7 +31,7 @@
 
 namespace blink {
 
-ScopedPageLoadDeferrer::ScopedPageLoadDeferrer(Page* exclusion) : m_detached(false)
+ScopedPageLoadDeferrer::ScopedPageLoadDeferrer(Page* exclusion)
 {
     const HashSet<Page*>& pages = Page::ordinaryPages();
     for (const Page* page : pages) {
@@ -57,36 +57,17 @@ ScopedPageLoadDeferrer::ScopedPageLoadDeferrer(Page* exclusion) : m_detached(fal
 
 void ScopedPageLoadDeferrer::detach()
 {
-    if (m_detached)
-        return;
-
     for (size_t i = 0; i < m_deferredFrames.size(); ++i) {
         if (Page* page = m_deferredFrames[i]->page())
             page->setDefersLoading(false);
     }
 
     Platform::current()->currentThread()->scheduler()->resumeTimerQueue();
-    m_detached = true;
-}
-
-#if ENABLE(OILPAN)
-void ScopedPageLoadDeferrer::dispose()
-{
-    detach();
-    m_deferredFrames.clear();
 }
-#endif
 
 ScopedPageLoadDeferrer::~ScopedPageLoadDeferrer()
 {
     detach();
 }
 
-DEFINE_TRACE(ScopedPageLoadDeferrer)
-{
-#if ENABLE(OILPAN)
-    visitor->trace(m_deferredFrames);
-#endif
-}
-
 } // namespace blink

third_party/WebKit/Source/core/page/ScopedPageLoadDeferrer.h

@@ -30,24 +30,17 @@ namespace blink {
 class LocalFrame;
 class Page;
 
-class CORE_EXPORT ScopedPageLoadDeferrer final : public NoBaseWillBeGarbageCollectedFinalized<ScopedPageLoadDeferrer> {
+class CORE_EXPORT ScopedPageLoadDeferrer final {
     WTF_MAKE_NONCOPYABLE(ScopedPageLoadDeferrer);
-    WTF_MAKE_FAST_ALLOCATED_WILL_BE_REMOVED(ScopedPageLoadDeferrer);
+    WTF_MAKE_FAST_ALLOCATED(ScopedPageLoadDeferrer);
 public:
-    ScopedPageLoadDeferrer(Page* exclusion = nullptr);
+    explicit ScopedPageLoadDeferrer(Page* exclusion = nullptr);
     ~ScopedPageLoadDeferrer();
 
-#if ENABLE(OILPAN)
-    void dispose();
-#endif
-
-    DECLARE_TRACE();
-
 private:
     void detach();
 
-    WillBeHeapVector<RefPtrWillBeMember<LocalFrame>, 16> m_deferredFrames;
-    bool m_detached;
+    Vector<RefPtrWillBePersistent<LocalFrame>, 16> m_deferredFrames;
 };
 
 } // namespace blink

third_party/WebKit/Source/web/WebViewImpl.cpp

@@ -222,10 +222,10 @@ const double WebView::maxTextSizeMultiplier = 3.0;
 
 // Used to defer all page activity in cases where the embedder wishes to run
 // a nested event loop. Using a stack enables nesting of message loop invocations.
-static WillBeHeapVector<RawPtrWillBeMember<ScopedPageLoadDeferrer>>& pageLoadDeferrerStack()
+static Vector<OwnPtr<ScopedPageLoadDeferrer>>& pageLoadDeferrerStack()
 {
-    DEFINE_STATIC_LOCAL(OwnPtrWillBePersistent<WillBeHeapVector<RawPtrWillBeMember<ScopedPageLoadDeferrer>>>, deferrerStack, (adoptPtrWillBeNoop(new WillBeHeapVector<RawPtrWillBeMember<ScopedPageLoadDeferrer>>())));
-    return *deferrerStack;
+    DEFINE_STATIC_LOCAL(Vector<OwnPtr<ScopedPageLoadDeferrer>>, deferrerStack, ());
+    return deferrerStack;
 }
 
 // Ensure that the WebDragOperation enum values stay in sync with the original
@@ -356,19 +356,12 @@ void WebView::resetVisitedLinkState()
 
 void WebView::willEnterModalLoop()
 {
-    pageLoadDeferrerStack().append(new ScopedPageLoadDeferrer());
+    pageLoadDeferrerStack().append(adoptPtr(new ScopedPageLoadDeferrer()));
 }
 
 void WebView::didExitModalLoop()
 {
     ASSERT(pageLoadDeferrerStack().size());
-
-    ScopedPageLoadDeferrer* deferrer = pageLoadDeferrerStack().last();
-#if ENABLE(OILPAN)
-    deferrer->dispose();
-#else
-    delete deferrer;
-#endif
     pageLoadDeferrerStack().removeLast();
 }