Add infrastructure for partial layouts

Source/core/dom/Document.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) Research In Motion Limited 2010-2011. All rights reserved.
@@ skipping 133 matching lines @@
 #include "core/page/MouseEventWithHitTestResults.h"
 #include "core/page/Page.h"
 #include "core/page/PageConsole.h"
 #include "core/page/PointerLockController.h"
 #include "core/page/Settings.h"
 #include "core/page/animation/AnimationController.h"
 #include "core/page/scrolling/ScrollingCoordinator.h"
 #include "core/platform/DateComponents.h"
 #include "core/platform/HistogramSupport.h"
 #include "core/platform/Language.h"
+#include "core/platform/ScrollbarTheme.h"
 #include "core/platform/Timer.h"
 #include "core/platform/chromium/TraceEvent.h"
 #include "core/platform/network/HTTPParsers.h"
 #include "core/platform/text/PlatformLocale.h"
 #include "core/platform/text/SegmentedString.h"
 #include "core/rendering/HitTestRequest.h"
 #include "core/rendering/HitTestResult.h"
 #include "core/rendering/RenderView.h"
 #include "core/rendering/RenderWidget.h"
 #include "core/rendering/TextAutosizer.h"
@@ skipping 1581 matching lines @@
         oe->document()->updateLayout();
 
     updateStyleIfNeeded();
 
     StackStats::LayoutCheckPoint layoutCheckPoint;
 
     // Only do a layout if changes have occurred that make it necessary.
     if (frameView && renderer() && (frameView->layoutPending() || renderer()->needsLayout()))
         frameView->layout();
 
+    if (frameView)
+        frameView->resetPartialLayoutState();
+
     setNeedsFocusedElementCheck();
 }
 
 void Document::setNeedsFocusedElementCheck()
 {
     // FIXME: Using a Task doesn't look a good idea.
     if (!m_focusedElement || m_didPostCheckFocusedElementTask)
         return;
     postTask(CheckFocusedElementTask::create());
     m_didPostCheckFocusedElementTask = true;
@@ skipping 26 matching lines @@
             // may not have had their real style calculated yet. Normally this gets cleaned when style sheets arrive
             // but here we need up-to-date style immediately.
             recalcStyle(Force);
     }
 
     updateLayout();
 
     m_ignorePendingStylesheets = oldIgnore;
 }
 
+void Document::tryPartialUpdateLayoutIgnorePendingStylesheets(RenderObject* stopLayoutAtRenderer)
+{
+    if (stopLayoutAtRenderer) {
+        // Non-overlay scrollbars can cause layout during layout.
+        // FIXME: Temporarily ignore non-overlay scrollbars for test coverage.
+        if (true || ScrollbarTheme::theme()->usesOverlayScrollbars()) {
+            // FIXME: Text autosizing will not work with partial layout.
+            bool canPartialLayout = true;
+            RenderObject* renderer = stopLayoutAtRenderer;
+            do {
+                if (!renderer->supportsPartialLayout()) {
+                    canPartialLayout = false;
+                    break;
+                }
+            } while ((renderer = renderer->parent()));
+            if (canPartialLayout)
+                view()->setStopLayoutAtRenderer(stopLayoutAtRenderer);
+        }
+    }
+
+    updateLayoutIgnorePendingStylesheets();
+}
+
 PassRefPtr<RenderStyle> Document::styleForElementIgnoringPendingStylesheets(Element* element)
 {
     ASSERT_ARG(element, element->document() == this);
     TemporaryChange<bool> ignoreStyleSheets(m_ignorePendingStylesheets, true);
     return styleResolver()->styleForElement(element, element->parentNode() ? element->parentNode()->computedStyle() : 0);
 }
 
 PassRefPtr<RenderStyle> Document::styleForPage(int pageIndex)
 {
     return styleResolver()->styleForPage(pageIndex);
@@ skipping 3413 matching lines @@
 {
     return DocumentLifecycleNotifier::create(this);
 }
 
 DocumentLifecycleNotifier* Document::lifecycleNotifier()
 {
     return static_cast<DocumentLifecycleNotifier*>(ScriptExecutionContext::lifecycleNotifier());
 }
 
 } // namespace WebCore