Refactor fixed layout mode

Source/core/page/FrameView.cpp

Index: Source/core/page/FrameView.cpp
diff --git a/Source/core/page/FrameView.cpp b/Source/core/page/FrameView.cpp
index 7a898dfcce0d99adab4a31de5b2092eab53556c1..ee330e35f9f0e42ad04092958a62efadbc480dd5 100644
--- a/Source/core/page/FrameView.cpp
+++ b/Source/core/page/FrameView.cpp
@@ -203,6 +203,8 @@ PassRefPtr<FrameView> FrameView::create(Frame* frame, const IntSize& initialSize
 {
     RefPtr<FrameView> view = adoptRef(new FrameView(frame));
     view->Widget::setFrameRect(IntRect(view->location(), initialSize));
+    view->setLayoutSize(initialSize);
+
     view->show();
     return view.release();
 }
@@ -1056,7 +1058,7 @@ void FrameView::layout(bool allowSubtree)
 
             LayoutSize oldSize = m_size;
 
-            m_size = LayoutSize(layoutWidth(), layoutHeight());
+            m_size = LayoutSize(layoutSize().width(), layoutSize().height());
 
             if (oldSize != m_size) {
                 m_doFullRepaint = true;
@@ -1112,7 +1114,7 @@ void FrameView::layout(bool allowSubtree)
     updateCanBlitOnScrollRecursively();
 
     if (document->hasListenerType(Document::OVERFLOWCHANGED_LISTENER))
-        updateOverflowStatus(layoutWidth() < contentsWidth(), layoutHeight() < contentsHeight());
+        updateOverflowStatus(layoutSize().width() < contentsWidth(), layoutSize().height() < contentsHeight());
 
     scheduleOrPerformPostLayoutTasks();
 
@@ -1606,6 +1608,19 @@ void FrameView::setViewportConstrainedObjectsNeedLayout()
     }
 }
 
+IntSize FrameView::layoutSize(IncludeScrollbarsInRect scrollbarInclusion) const
+{
+    return scrollbarInclusion == ExcludeScrollbars ? excludeScrollbars(m_layoutSize) : m_layoutSize;
+}
+
+void FrameView::setLayoutSize(const IntSize& size)
+{
+    if (m_layoutSize == size)
+        return;
+
+    m_layoutSize = size;
+    contentsResized();
+}
 
 void FrameView::scrollPositionChanged()
 {
@@ -1722,7 +1737,7 @@ void FrameView::contentsResized()
     setNeedsLayout();
 }
 
-void FrameView::visibleContentsResized()
+void FrameView::scrollbarExistenceDidChange()
 {
     // We check to make sure the view is attached to a frame() as this method can
     // be triggered before the view is attached by Frame::createView(...) setting
@@ -1731,7 +1746,7 @@ void FrameView::visibleContentsResized()
     if (!frame().view())
         return;
 
-    if (!useFixedLayout() && needsLayout())
+    if (!m_frame->page()->settings().viewportEnabled() && needsLayout())

[aelias_OOO_until_Jul13, 2013/10/01 05:09:30]

Checking viewportEnabled here doesn't seem very principled.  How about checking
if they're overlay scrollbars instead?

[bokan, 2013/10/02 17:44:01]

A few unit tests in WebFrameTest fail when I check for that instead. I'm
assuming they're checking Clank/WebView specific behaviour but the tests don't
have the lverlay scrollbars theme enabled. Does WebView use overlay scrollbars
as well? If it does I can fix the tests and change this. 

[aelias_OOO_until_Jul13, 2013/10/02 18:59:59]

Yes, both Clank and WebView always use overlay scrollbars.  You can go ahead and
update all the WebFrameTests that enable the viewport tag to also activate the
overlay scrollbar theme.

[bokan, 2013/10/02 21:27:26]

Done.

         layout();
 
     if (RenderView* renderView = this->renderView()) {
@@ -2409,6 +2424,7 @@ void FrameView::autoSizeIfEnabled()
             break;
 
         resize(newSize.width(), newSize.height());
+        setLayoutSize(newSize);
         // Force the scrollbar state to avoid the scrollbar code adding them and causing them to be needed. For example,
         // a vertical scrollbar may cause text to wrap and thus increase the height (which is the only reason the scollbar is needed).
         setVerticalScrollbarLock(false);
@@ -3415,4 +3431,18 @@ bool FrameView::isMainFrame() const
     return m_frame->page() && m_frame->page()->mainFrame() == m_frame;
 }
 
+void FrameView::frameRectsChanged()
+{
+    Document* doc = m_frame->document();
+    bool layoutSizeIsExplicitlySet = m_frame->page() && m_frame->page()->mainFrame() == m_frame

[aelias_OOO_until_Jul13, 2013/10/01 05:09:30]

Instead of this, how about a public method
FrameView::setLayoutSizeMatchesFrameSize(bool), make the boolean default to true
and only set it false from WebViewImpl?

[bokan, 2013/10/02 17:44:01]

Done, only I set it false from Frame::createView

+        && doc && (doc->isHTMLDocument() || doc->isXHTMLDocument());
+
+    // Non-main frames' layout size should always match the frame size. For main frames we
+    // explicitly set the layout size from WebViewImpl
+    if (!layoutSizeIsExplicitlySet)
+        setLayoutSize(frameRect().size());
+
+    ScrollView::frameRectsChanged();
+}
+
 } // namespace WebCore