Clarify the size of a document view (a.k.a layout size) that causes FrameView to emit the resize ev…

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 ba2e4e7c21899666a3bf348d98f73748a536113e..cbbbfa367e5919cb998ee982b3f504bbbeddd6c0 100644
--- a/Source/core/page/FrameView.cpp
+++ b/Source/core/page/FrameView.cpp
@@ -131,6 +131,14 @@ static RenderLayer::UpdateLayerPositionsFlags updateLayerPositionFlags(RenderLay
     return flags;
 }
 
+// The spec DOM Level 2 Events states that the resize event occurs when document view size (a.k.a layout size) is changed. Refer to http://www.w3.org/TR/DOM-Level-2-Events/events.html
+// However, showing/hiding scrollbars shouldn't be considered a layout size change. Refer to webkit.org/b/80242
+// viewportSize() is used to compare layout sizes between before and after to emit a resize event.
+static inline IntSize viewportSize(const FrameView* view)

[aelias_OOO_until_Jul13, 2013/05/29 18:47:28]

I suggest not having this static method and just calling view->layoutSize(). 
Please move the comment into your layout test.

+{
+    return view->layoutSize(ScrollView::IncludeScrollbars);
+}
+
 Pagination::Mode paginationModeForRenderStyle(RenderStyle* style)
 {
     EOverflow overflow = style->overflowY();
@@ -986,7 +994,7 @@ void FrameView::layout(bool allowSubtree)
 
                     m_firstLayout = false;
                     m_firstLayoutCallbackPending = true;
-                    m_lastViewportSize = visibleContentRect(IncludeScrollbars).size();
+                    m_lastViewportSize = viewportSize(this);
                     m_lastZoomFactor = root->style()->zoom();
 
                     // Set the initial vMode to AlwaysOn if we're auto.
@@ -2286,8 +2294,7 @@ void FrameView::performPostLayoutTasks()
     // Refetch render view since it can be destroyed by updateWidget() call above.
     renderView = this->renderView();
     if (renderView && !renderView->printing()) {
-        IntSize currentSize;
-        currentSize = visibleContentRect(IncludeScrollbars).size();
+        IntSize currentSize = viewportSize(this);
         float currentZoomFactor = renderView->style()->zoom();
         bool resized = !m_firstLayout && (currentSize != m_lastViewportSize || currentZoomFactor != m_lastZoomFactor);
         m_lastViewportSize = currentSize;