Updated WebKit from /home/shausman/src/webkit/trunk to qtwebkit/qtwebkit-4.6 ( d95c54951e7af2aa7def4346a142b2162bd89bbd )

Changes in WebKit/qt since the last update:

 https://bugs.webkit.org/show_bug.cgi?id=33408 -- Add flag IGNORE_FIXED_BACKGROUNDS (disabled by default) to ignore fixed background images and accelerate web page scrolling on low-powered/mobile devices
 https://bugs.webkit.org/show_bug.cgi?id=34168 -- [Qt] Enable FAST_MOBILE_SCROLLING on Qt embedded platforms
 https://bugs.webkit.org/show_bug.cgi?id=33150 -- Do not render the full frame when there is some elements with fixed positioning

11 files changed, 174 insertions, 7 deletions

diff --git a/src/3rdparty/webkit/VERSION b/src/3rdparty/webkit/VERSION
index a2d5f37..def66ef 100644
--- a/src/3rdparty/webkit/VERSION
+++ b/src/3rdparty/webkit/VERSION
@@ -8,4 +8,4 @@ The commit imported was from the
 
 and has the sha1 checksum
 
-        266a6c4f1938dd9edf4a8125faf91c62495e3ce2
+        d95c54951e7af2aa7def4346a142b2162bd89bbd
diff --git a/src/3rdparty/webkit/WebCore/ChangeLog b/src/3rdparty/webkit/WebCore/ChangeLog
index a3f70d3..869e225 100644
--- a/src/3rdparty/webkit/WebCore/ChangeLog
+++ b/src/3rdparty/webkit/WebCore/ChangeLog
@@ -1,3 +1,49 @@
+2010-01-31  Benjamin Poulain  <benjamin.poulain@nokia.com>
+
+        Reviewed by Eric Seidel.
+
+        [Qt] Enable FAST_MOBILE_SCROLLING on Qt embedded platforms
+        https://bugs.webkit.org/show_bug.cgi?id=34168
+
+        Enable FAST_MOBILE_SCROLLING for Qt on Maemo 5, Linux embedded
+        and Symbian
+
+        * WebCore.pro:
+
+2010-01-19  Daniel Bates  <dbates@rim.com>
+
+        Reviewed by Adam Treat.
+
+        https://bugs.webkit.org/show_bug.cgi?id=33408
+
+        Implements an optimization to ignore fixed background images
+        (i.e. background-attachment: fixed) when a page does not contain
+        any fixed position elements so as to allow fast repaints (via bit
+        blit) when scrolling a page.
+
+        Currently, if a page has elements that specify either a fixed
+        background or a fixed position then we perform a slow repaint
+        (i.e disable blitting) so as to avoid rendering artifacts.
+        However, on low-powered/mobile devices slow repaints can cause
+        noticeable delays when scrolling a page with a fixed background
+        image. By sacrificing support for fixed background images when
+        there are no fixed elements on the page and with come care, we
+        don't need to force slow repaints and can avoid rendering artifacts.
+        Hence, on such devices we can improve the responsiveness of
+        scrolling a page with a fixed background image.
+
+        Note, this optimization is only enabled if the WebKit is built
+        with FAST_MOBILE_SCROLLING enabled.
+
+        Tests: fast/fast-mobile-scrolling/fixed-position-element.html
+               fast/fast-mobile-scrolling/no-fixed-position-elements.html
+
+        * rendering/RenderBoxModelObject.cpp:
+        (WebCore::RenderBoxModelObject::calculateBackgroundImageGeometry):
+        Disable fixed background attachment if we can blit on scroll.
+        * rendering/RenderObject.cpp:
+        (WebCore::RenderObject::styleWillChange):
+
 2010-03-11  Simon Hausmann  <simon.hausmann@nokia.com>
 
         Reviewed by Tor Arne Vestbø.
diff --git a/src/3rdparty/webkit/WebCore/WebCore.pro b/src/3rdparty/webkit/WebCore/WebCore.pro
index 5654a18..735c8ef 100644
--- a/src/3rdparty/webkit/WebCore/WebCore.pro
+++ b/src/3rdparty/webkit/WebCore/WebCore.pro
@@ -162,6 +162,10 @@ contains(DEFINES, ENABLE_SINGLE_THREADED=1) {
     DEFINES += ENABLE_SVG_FONTS=0 ENABLE_SVG_FOREIGN_OBJECT=0 ENABLE_SVG_ANIMATION=0 ENABLE_SVG_AS_IMAGE=0 ENABLE_SVG_USE=0
 }
 
+mameo5|symbian|embedded {
+    DEFINES += ENABLE_FAST_MOBILE_SCROLLING=1
+}
+
 # HTML5 ruby support
 !contains(DEFINES, ENABLE_RUBY=.): DEFINES += ENABLE_RUBY=1
 
diff --git a/src/3rdparty/webkit/WebCore/page/FrameView.cpp b/src/3rdparty/webkit/WebCore/page/FrameView.cpp
index bc4e4f2..4c3a0ab 100644
--- a/src/3rdparty/webkit/WebCore/page/FrameView.cpp
+++ b/src/3rdparty/webkit/WebCore/page/FrameView.cpp
@@ -106,6 +106,7 @@ struct ScheduledEvent {
 FrameView::FrameView(Frame* frame)
     : m_frame(frame)
     , m_slowRepaintObjectCount(0)
+    , m_fixedObjectCount(0)
     , m_layoutTimer(this, &FrameView::layoutTimerFired)
     , m_layoutRoot(0)
     , m_postLayoutTasksTimer(this, &FrameView::postLayoutTimerFired)
@@ -735,7 +736,7 @@ String FrameView::mediaType() const
 
 bool FrameView::useSlowRepaints() const
 {
-    return m_useSlowRepaints || m_slowRepaintObjectCount > 0 || m_isOverlapped || !m_contentIsOpaque;
+    return m_useSlowRepaints || m_slowRepaintObjectCount > 0 || (platformWidget() && m_fixedObjectCount > 0) || m_isOverlapped || !m_contentIsOpaque;
 }
 
 void FrameView::setUseSlowRepaints()
@@ -759,6 +760,78 @@ void FrameView::removeSlowRepaintObject()
         setCanBlitOnScroll(!useSlowRepaints());
 }
 
+void FrameView::addFixedObject()
+{
+    if (!m_fixedObjectCount && platformWidget())
+        setCanBlitOnScroll(false);
+    ++m_fixedObjectCount;
+}
+
+void FrameView::removeFixedObject()
+{
+    ASSERT(m_fixedObjectCount > 0);
+    m_fixedObjectCount--;
+    if (!m_fixedObjectCount)
+        setCanBlitOnScroll(!useSlowRepaints());
+}
+
+void FrameView::scrollContentsFastPath(const IntSize& scrollDelta, const IntRect& rectToScroll, const IntRect& clipRect)
+{
+    const size_t fixedObjectThreshold = 5;
+
+    ListHashSet<RenderBox*>* positionedObjects = 0;
+    if (RenderView* root = m_frame->contentRenderer())
+        positionedObjects = root->positionedObjects();
+
+    if (!positionedObjects || positionedObjects->isEmpty()) {
+        hostWindow()->scroll(scrollDelta, rectToScroll, clipRect);
+        return;
+    }
+
+    // Get the rects of the fixed objects visible in the rectToScroll
+    Vector<IntRect, fixedObjectThreshold> subRectToUpdate;
+    bool updateInvalidatedSubRect = true;
+    ListHashSet<RenderBox*>::const_iterator end = positionedObjects->end();
+    for (ListHashSet<RenderBox*>::const_iterator it = positionedObjects->begin(); it != end; ++it) {
+        RenderBox* renderBox = *it;
+        if (renderBox->style()->position() != FixedPosition)
+            continue;
+        IntRect topLevelRect;
+        IntRect updateRect = renderBox->paintingRootRect(topLevelRect);
+        updateRect.move(-scrollX(), -scrollY());
+        updateRect.intersect(rectToScroll);
+        if (!updateRect.isEmpty()) {
+            if (subRectToUpdate.size() >= fixedObjectThreshold) {
+                updateInvalidatedSubRect = false;
+                break;
+            }
+            subRectToUpdate.append(updateRect);
+        }
+    }
+
+    // Scroll the view
+    if (updateInvalidatedSubRect) {
+        // 1) scroll
+        hostWindow()->scroll(scrollDelta, rectToScroll, clipRect);
+
+        // 2) update the area of fixed objets that has been invalidated
+        size_t fixObjectsCount = subRectToUpdate.size();
+        for (size_t i = 0; i < fixObjectsCount; ++i) {
+            IntRect updateRect = subRectToUpdate[i];
+            IntRect scrolledRect = updateRect;
+            scrolledRect.move(scrollDelta);
+            updateRect.unite(scrolledRect);
+            updateRect.intersect(rectToScroll);
+            hostWindow()->repaint(updateRect, true, false, true);
+        }
+    } else {
+        // the number of fixed objects exceed the threshold, so we repaint everything.
+        IntRect updateRect = clipRect;
+        updateRect.intersect(rectToScroll);
+        hostWindow()->repaint(updateRect, true, false, true);
+    }
+}
+
 void FrameView::setIsOverlapped(bool isOverlapped)
 {
     if (isOverlapped == m_isOverlapped)
diff --git a/src/3rdparty/webkit/WebCore/page/FrameView.h b/src/3rdparty/webkit/WebCore/page/FrameView.h
index 3d17d2c..5243c02 100644
--- a/src/3rdparty/webkit/WebCore/page/FrameView.h
+++ b/src/3rdparty/webkit/WebCore/page/FrameView.h
@@ -143,6 +143,9 @@ public:
     void addSlowRepaintObject();
     void removeSlowRepaintObject();
 
+    void addFixedObject();
+    void removeFixedObject();
+
     void beginDeferredRepaints();
     void endDeferredRepaints();
     void checkStopDelayingDeferredRepaints();
@@ -196,6 +199,9 @@ public:
     bool isFrameViewScrollCorner(RenderScrollbarPart* scrollCorner) const { return m_scrollCorner == scrollCorner; }
     void invalidateScrollCorner();
 
+protected:
+    virtual void scrollContentsFastPath(const IntSize& scrollDelta, const IntRect& rectToScroll, const IntRect& clipRect);
+
 private:
     FrameView(Frame*);
 
@@ -261,6 +267,7 @@ private:
     bool m_isOverlapped;
     bool m_contentIsOpaque;
     unsigned m_slowRepaintObjectCount;
+    unsigned m_fixedObjectCount;
 
     int m_borderX, m_borderY;
 
diff --git a/src/3rdparty/webkit/WebCore/platform/ScrollView.cpp b/src/3rdparty/webkit/WebCore/platform/ScrollView.cpp
index e67daf9..9e15c43 100644
--- a/src/3rdparty/webkit/WebCore/platform/ScrollView.cpp
+++ b/src/3rdparty/webkit/WebCore/platform/ScrollView.cpp
@@ -509,7 +509,7 @@ void ScrollView::scrollContents(const IntSize& scrollDelta)
 
     if (canBlitOnScroll()) { // The main frame can just blit the WebView window
        // FIXME: Find a way to blit subframes without blitting overlapping content
-       hostWindow()->scroll(-scrollDelta, scrollViewRect, clipRect);
+       scrollContentsFastPath(-scrollDelta, scrollViewRect, clipRect);
     } else { 
        // We need to go ahead and repaint the entire backing store.  Do it now before moving the
        // windowed plugins.
@@ -524,6 +524,11 @@ void ScrollView::scrollContents(const IntSize& scrollDelta)
     hostWindow()->paint();
 }
 
+void ScrollView::scrollContentsFastPath(const IntSize& scrollDelta, const IntRect& rectToScroll, const IntRect& clipRect)
+{
+    hostWindow()->scroll(scrollDelta, rectToScroll, clipRect);
+}
+
 IntPoint ScrollView::windowToContents(const IntPoint& windowPoint) const
 {
     IntPoint viewPoint = convertFromContainingWindow(windowPoint);
diff --git a/src/3rdparty/webkit/WebCore/platform/ScrollView.h b/src/3rdparty/webkit/WebCore/platform/ScrollView.h
index 5dacff5..7060d07 100644
--- a/src/3rdparty/webkit/WebCore/platform/ScrollView.h
+++ b/src/3rdparty/webkit/WebCore/platform/ScrollView.h
@@ -244,6 +244,9 @@ protected:
     IntRect scrollCornerRect() const;
     virtual void updateScrollCorner();
     virtual void paintScrollCorner(GraphicsContext*, const IntRect& cornerRect);
+
+    // Scroll the content by blitting the pixels
+    virtual void scrollContentsFastPath(const IntSize& scrollDelta, const IntRect& rectToScroll, const IntRect& clipRect);
     
 private:
     RefPtr<Scrollbar> m_horizontalScrollbar;
diff --git a/src/3rdparty/webkit/WebCore/rendering/RenderBlock.h b/src/3rdparty/webkit/WebCore/rendering/RenderBlock.h
index 7ba5fce..3300d01 100644
--- a/src/3rdparty/webkit/WebCore/rendering/RenderBlock.h
+++ b/src/3rdparty/webkit/WebCore/rendering/RenderBlock.h
@@ -75,6 +75,7 @@ public:
     void insertPositionedObject(RenderBox*);
     void removePositionedObject(RenderBox*);
     void removePositionedObjects(RenderBlock*);
+    ListHashSet<RenderBox*>* positionedObjects() const { return m_positionedObjects; }
 
     void addPercentHeightDescendant(RenderBox*);
     static void removePercentHeightDescendant(RenderBox*);
diff --git a/src/3rdparty/webkit/WebCore/rendering/RenderBox.cpp b/src/3rdparty/webkit/WebCore/rendering/RenderBox.cpp
index 1df82a4..7ca2ff8 100644
--- a/src/3rdparty/webkit/WebCore/rendering/RenderBox.cpp
+++ b/src/3rdparty/webkit/WebCore/rendering/RenderBox.cpp
@@ -145,6 +145,16 @@ void RenderBox::styleWillChange(StyleDifference diff, const RenderStyle* newStyl
                 removeFloatingOrPositionedChildFromBlockLists();
         }
     }
+    if (FrameView *frameView = view()->frameView()) {
+        bool newStyleIsFixed = newStyle && newStyle->position() == FixedPosition;
+        bool oldStyleIsFixed = style() && style()->position() == FixedPosition;
+        if (newStyleIsFixed != oldStyleIsFixed) {
+            if (newStyleIsFixed)
+                frameView->addFixedObject();
+            else
+                frameView->removeFixedObject();
+        }
+    }
 
     RenderBoxModelObject::styleWillChange(diff, newStyle);
 }
diff --git a/src/3rdparty/webkit/WebCore/rendering/RenderBoxModelObject.cpp b/src/3rdparty/webkit/WebCore/rendering/RenderBoxModelObject.cpp
index 23dad2d..9d0f1ed 100644
--- a/src/3rdparty/webkit/WebCore/rendering/RenderBoxModelObject.cpp
+++ b/src/3rdparty/webkit/WebCore/rendering/RenderBoxModelObject.cpp
@@ -557,6 +557,17 @@ void RenderBoxModelObject::calculateBackgroundImageGeometry(const FillLayer* fil
     // Determine the background positioning area and set destRect to the background painting area.
     // destRect will be adjusted later if the background is non-repeating.
     bool fixedAttachment = fillLayer->attachment() == FixedBackgroundAttachment;
+
+#if ENABLE(FAST_MOBILE_SCROLLING)
+    if (view()->frameView() && view()->frameView()->canBlitOnScroll()) {
+        // As a side effect of an optimization to blit on scroll, we do not honor the CSS
+        // property "background-attachment: fixed" because it may result in rendering
+        // artifacts. Note, these artifacts only appear if we are blitting on scroll of
+        // a page that has fixed background images.
+        fixedAttachment = false;
+    }
+#endif
+
     if (!fixedAttachment) {
         destRect = IntRect(tx, ty, w, h);
 
diff --git a/src/3rdparty/webkit/WebCore/rendering/RenderObject.cpp b/src/3rdparty/webkit/WebCore/rendering/RenderObject.cpp
index a10ffd9..199de4a 100644
--- a/src/3rdparty/webkit/WebCore/rendering/RenderObject.cpp
+++ b/src/3rdparty/webkit/WebCore/rendering/RenderObject.cpp
@@ -1591,10 +1591,17 @@ void RenderObject::styleWillChange(StyleDifference diff, const RenderStyle* newS
         s_affectsParentBlock = false;
 
     if (view()->frameView()) {
-        // FIXME: A better solution would be to only invalidate the fixed regions when scrolling.  It's overkill to
-        // prevent the entire view from blitting on a scroll.
-        bool newStyleSlowScroll = newStyle && (newStyle->position() == FixedPosition || newStyle->hasFixedBackgroundImage());
-        bool oldStyleSlowScroll = m_style && (m_style->position() == FixedPosition || m_style->hasFixedBackgroundImage());
+        bool shouldBlitOnFixedBackgroundImage = false;
+#if ENABLE(FAST_MOBILE_SCROLLING)
+        // On low-powered/mobile devices, preventing blitting on a scroll can cause noticeable delays
+        // when scrolling a page with a fixed background image. As an optimization, assuming there are
+        // no fixed positoned elements on the page, we can acclerate scrolling (via blitting) if we
+        // ignore the CSS property "background-attachment: fixed".
+        shouldBlitOnFixedBackgroundImage = true;
+#endif
+
+        bool newStyleSlowScroll = newStyle && !shouldBlitOnFixedBackgroundImage && newStyle->hasFixedBackgroundImage();
+        bool oldStyleSlowScroll = m_style && !shouldBlitOnFixedBackgroundImage && m_style->hasFixedBackgroundImage();
         if (oldStyleSlowScroll != newStyleSlowScroll) {
             if (oldStyleSlowScroll)
                 view()->frameView()->removeSlowRepaintObject();