Aura overlay scrollbars adjust color for dark backgrounds

third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.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@gmail.com>
@@ skipping 839 matching lines @@
 }
 
 void PaintLayerScrollableArea::updateAfterStyleChange(
     const ComputedStyle* oldStyle) {
   // Don't do this on first style recalc, before layout has ever happened.
   if (!overflowRect().size().isZero()) {
     updateScrollableAreaSet(hasScrollableHorizontalOverflow() ||
                             hasScrollableVerticalOverflow());
   }
 
+  // Whenever background changes on the scrollable element, the scroll bar
+  // overlay style might need to be changed to have contrast against the
+  // background.
+  // Skip the need scrollbar check, because we dont know do we need a scrollbar
+  // when this method get called.
+  Color oldBackground;
+  if (oldStyle) {
+    oldBackground = oldStyle->visitedDependentColor(CSSPropertyBackgroundColor);
+  }
+  Color newBackground =
+      box().style()->visitedDependentColor(CSSPropertyBackgroundColor);
+
+  if (newBackground != oldBackground) {
+    recalculateScrollbarOverlayColorTheme(newBackground);
+  }
+
   bool needsHorizontalScrollbar;
   bool needsVerticalScrollbar;
   // We add auto scrollbars only during layout to prevent spurious activations.
   computeScrollbarExistence(needsHorizontalScrollbar, needsVerticalScrollbar,
                             ForbidAddingAutoBars);
 
   // Avoid some unnecessary computation if there were and will be no scrollbars.
   if (!hasScrollbar() && !needsHorizontalScrollbar && !needsVerticalScrollbar)
     return;
 
@@ skipping 17 matching lines @@
   // FIXME: Need to detect a swap from custom to native scrollbars (and vice
   // versa).
   if (horizontalScrollbar())
     horizontalScrollbar()->styleChanged();
   if (verticalScrollbar())
     verticalScrollbar()->styleChanged();
 
   updateScrollCornerStyle();
   updateResizerAreaSet();
   updateResizerStyle();
-
-  // Whenever background changes on the scrollable element, the scroll bar
-  // overlay style might need to be changed to have contrast against the
-  // background.
-  Color oldBackground;
-  if (oldStyle) {
-    oldBackground = oldStyle->visitedDependentColor(CSSPropertyBackgroundColor);
-  }
-  Color newBackground =
-      box().style()->visitedDependentColor(CSSPropertyBackgroundColor);
-
-  if (newBackground != oldBackground) {
-    recalculateScrollbarOverlayStyle(newBackground);
-  }
 }
 
 bool PaintLayerScrollableArea::updateAfterCompositingChange() {
   layer()->updateScrollingStateAfterCompositingChange();
   const bool layersChanged = m_topmostScrollChild != m_nextTopmostScrollChild;
   m_topmostScrollChild = m_nextTopmostScrollChild;
   m_nextTopmostScrollChild = nullptr;
   return layersChanged;
 }
 
@@ skipping 1030 matching lines @@
 
 void PaintLayerScrollableArea::DelayScrollOffsetClampScope::
     clampScrollableAreas() {
   for (auto& scrollableArea : *s_needsClamp)
     scrollableArea->clampScrollOffsetsAfterLayout();
   delete s_needsClamp;
   s_needsClamp = nullptr;
 }
 
 }  // namespace blink