Harden the machinery around updateWidgetPositions()

Source/core/frame/FrameView.cpp

 /*
  * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
  *                     1999 Lars Knoll <knoll@kde.org>
  *                     1999 Antti Koivisto <koivisto@kde.org>
  *                     2000 Dirk Mueller <mueller@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  *           (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
@@ skipping 47 matching lines @@
 #include "core/rendering/LayoutIndicator.h"
 #include "core/rendering/RenderCounter.h"
 #include "core/rendering/RenderEmbeddedObject.h"
 #include "core/rendering/RenderLayer.h"
 #include "core/rendering/RenderLayerCompositor.h"
 #include "core/rendering/RenderPart.h"
 #include "core/rendering/RenderScrollbar.h"
 #include "core/rendering/RenderScrollbarPart.h"
 #include "core/rendering/RenderTheme.h"
 #include "core/rendering/RenderView.h"
+#include "core/rendering/RenderWidget.h"
 #include "core/rendering/TextAutosizer.h"
 #include "core/rendering/style/RenderStyle.h"
 #include "core/rendering/svg/RenderSVGRoot.h"
 #include "core/svg/SVGDocument.h"
 #include "core/svg/SVGSVGElement.h"
 #include "platform/TraceEvent.h"
 #include "platform/fonts/FontCache.h"
 #include "platform/geometry/FloatRect.h"
 #include "platform/graphics/GraphicsContext.h"
 #include "platform/graphics/GraphicsLayerDebugInfo.h"
@@ skipping 867 matching lines @@
 void FrameView::scheduleOrPerformPostLayoutTasks()
 {
     if (m_postLayoutTasksTimer.isActive())
         return;
 
     // Partial layouts should not happen with synchronous post layouts.
     ASSERT(!(m_inSynchronousPostLayout && partialLayout().isStopping()));
 
     if (!m_inSynchronousPostLayout) {
         if (frame().document()->shouldDisplaySeamlesslyWithParent()) {
-            if (RenderView* renderView = this->renderView())
-                renderView->updateWidgetPositions();
+            updateWidgetPositions();
         } else {
             m_inSynchronousPostLayout = true;
             // Calls resumeScheduledEvents()
             performPostLayoutTasks();
             m_inSynchronousPostLayout = false;
         }
     }
 
     if (!m_postLayoutTasksTimer.isActive() && (needsLayout() || m_inSynchronousPostLayout || frame().document()->shouldDisplaySeamlesslyWithParent())) {
         // If we need layout or are already in a synchronous call to postLayoutTasks(),
@@ skipping 289 matching lines @@
     if (!firstChild || !firstChild->isBox())
         return 0;
 
     // Curently only embedded SVG documents participate in the size-negotiation logic.
     if (firstChild->isSVGRoot())
         return toRenderBox(firstChild);
 
     return 0;
 }
 
+
+void FrameView::addWidget(RenderWidget* object)
+{
+    m_widgets.add(object);
+}
+
+void FrameView::removeWidget(RenderWidget* object)
+{
+    m_widgets.remove(object);
+}
+
+void FrameView::updateWidgetPositions()
+{
+    Vector<RefPtr<RenderWidget> > widgets;
+    copyToVector(m_widgets, widgets);
+
+    // Script or plugins could detach the frame so abort processing if that happens.
+
+    for (size_t i = 0; i < widgets.size() && renderView(); ++i)
+        widgets[i]->updateWidgetPosition();
+
+    for (size_t i = 0; i < widgets.size() && renderView(); ++i)
+        widgets[i]->widgetPositionsUpdated();
+}
+
 void FrameView::addWidgetToUpdate(RenderEmbeddedObject& object)
 {
     // Tell the DOM element that it needs a widget update.
     Node* node = object.node();
     if (node->hasTagName(objectTag) || node->hasTagName(embedTag))
         toHTMLPlugInElement(node)->setNeedsWidgetUpdate(true);
 
     m_widgetUpdateSet.add(&object);
 }
 
@@ skipping 451 matching lines @@
     }
 
     if (m_frame->document() && m_frame->document()->renderer()) {
         ResourceLoadPriorityOptimizer modifier;
         m_frame->document()->renderer()->didScroll(modifier);
     }
 }
 
 void FrameView::repaintFixedElementsAfterScrolling()
 {
+    RefPtr<FrameView> protect(this);
     // For fixed position elements, update widget positions and compositing layers after scrolling,
     // but only if we're not inside of layout.
     if (!m_nestedLayoutCount && hasViewportConstrainedObjects()) {
-        if (RenderView* renderView = this->renderView()) {
-            renderView->updateWidgetPositions();
+        updateWidgetPositions();
+        if (RenderView* renderView = this->renderView())
             renderView->layer()->updateLayerPositionsAfterDocumentScroll();
-        }
     }
 }
 
 void FrameView::updateFixedElementsAfterScrolling()
 {
     if (m_nestedLayoutCount <= 1 && hasViewportConstrainedObjects()) {
         if (RenderView* renderView = this->renderView())
             renderView->compositor()->setNeedsCompositingUpdate(CompositingUpdateOnScroll);
     }
 }
@@ skipping 539 matching lines @@
         if (m_isVisuallyNonEmpty && !m_frame->document()->didLayoutWithPendingStylesheets() && m_firstVisuallyNonEmptyLayoutCallbackPending) {
             m_firstVisuallyNonEmptyLayoutCallbackPending = false;
             // FIXME: This callback is probably not needed, but is currently used
             // by android for setting the background color.
             m_frame->loader().client()->dispatchDidFirstVisuallyNonEmptyLayout();
         }
     }
 
     FontFaceSet::didLayout(m_frame->document());
 
-    RenderView* renderView = this->renderView();
-    if (renderView)
-        renderView->updateWidgetPositions();
+    updateWidgetPositions();
+
+    // Plugins could have torn down the page inside updateWidgetPositions().
+    if (!renderView())
+        return;
 
     if (!m_updateWidgetsTimer.isActive())
         m_updateWidgetsTimer.startOneShot(0);
 
     if (Page* page = m_frame->page()) {
         if (ScrollingCoordinator* scrollingCoordinator = page->scrollingCoordinator())
             scrollingCoordinator->notifyLayoutUpdated();
     }
 
     scrollToAnchor();
@@ skipping 1194 matching lines @@
 void FrameView::willRemoveScrollbar(Scrollbar* scrollbar, ScrollbarOrientation orientation)
 {
     ScrollableArea::willRemoveScrollbar(scrollbar, orientation);
     if (AXObjectCache* cache = axObjectCache()) {
         cache->remove(scrollbar);
         cache->handleScrollbarUpdate(this);
     }
 }
 
 } // namespace WebCore