Textarea resize-able only to larger; min-height and min-width properly set

Source/core/rendering/RenderLayerScrollableArea.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@web.de>
  *   Randall Jesup <rjesup@wgate.com>
@@ skipping 76 matching lines @@
     ScrollableArea::setConstrainsScrollingToContentEdge(false);
 
     Node* node = m_box->node();
     if (node && node->isElementNode()) {
         // We save and restore only the scrollOffset as the other scroll values are recalculated.
         Element* element = toElement(node);
         m_scrollOffset = element->savedLayerScrollOffset();
         if (!m_scrollOffset.isZero())
             scrollAnimator()->setCurrentPosition(FloatPoint(m_scrollOffset.width(), m_scrollOffset.height()));
         element->setSavedLayerScrollOffset(IntSize());
+        element->setMinimumSizeForResizing(LayoutSize(LayoutUnit(m_box->style()->logicalMinWidth().value()), LayoutUnit(m_box->style()->logicalMinHeight().value())));

[Julien - ping for review, 2014/04/18 17:04:08]

This is wrong for several reasons:
1. it's not dynamic, which means that if you update min-width / min-height, you
won't update your limit and that seems wrong to me.
2. more importantly this will convert min-width: 50% into min-width: 50px which
is is just wrong.

To solve them:
1. You need to put the logic into updateAfterStyleChange.
2. You don't convert a Length into a LayoutUnit by calling Length.value(),
that's because some Length need some computations to be converted into absolute
pixels. That's handled by valueForLength().

[harpreet.sk, 2014/04/21 13:21:55]

 I have added the logic into updateAfterStyleChange. Now using valueForLength()
for converting Length to LayoutUnit. As per esprehn comment i also added check
to see if min-height or min-width is 0 or not. If it is 0 i had set the
min-value to 15px. I set it to 15px as Firefox also set it to 15px.

     }
 
     updateResizerAreaSet();
 }
 
 RenderLayerScrollableArea::~RenderLayerScrollableArea()
 {
     if (inResizeMode() && !m_box->documentBeingDestroyed()) {
         if (LocalFrame* frame = m_box->frame())
             frame->eventHandler().resizeScrollableAreaDestroyed();
@@ skipping 1222 matching lines @@
         ASSERT_NOT_REACHED();
     }
 
     float zoomFactor = m_box->style()->effectiveZoom();
 
     LayoutSize newOffset = offsetFromResizeCorner(document.view()->windowToContents(pos));
     newOffset.setWidth(newOffset.width() / zoomFactor);
     newOffset.setHeight(newOffset.height() / zoomFactor);
 
     LayoutSize currentSize = LayoutSize(m_box->width() / zoomFactor, m_box->height() / zoomFactor);
-    LayoutSize minimumSize = element->minimumSizeForResizing().shrunkTo(currentSize);
-    element->setMinimumSizeForResizing(minimumSize);
+    LayoutSize minimumSize = element->minimumSizeForResizing();
 
     LayoutSize adjustedOldOffset = LayoutSize(oldOffset.width() / zoomFactor, oldOffset.height() / zoomFactor);
     if (m_box->style()->shouldPlaceBlockDirectionScrollbarOnLogicalLeft()) {
         newOffset.setWidth(-newOffset.width());
         adjustedOldOffset.setWidth(-adjustedOldOffset.width());
     }
 
     LayoutSize difference = (currentSize + newOffset - adjustedOldOffset).expandedTo(minimumSize) - currentSize;
 
     bool isBoxSizingBorder = m_box->style()->boxSizing() == BORDER_BOX;
@@ skipping 154 matching lines @@
 void RenderLayerScrollableArea::setForceNeedsCompositedScrolling(ForceNeedsCompositedScrollingMode mode)
 {
     if (m_forceNeedsCompositedScrolling == mode)
         return;
 
     m_forceNeedsCompositedScrolling = mode;
     layer()->didUpdateNeedsCompositedScrolling();
 }
 
 } // Namespace WebCore