Improved the reporting of background color information.

third_party/WebKit/Source/modules/accessibility/AXLayoutObject.cpp

 /*
 * Copyright (C) 2008 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1.  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 815 matching lines @@
 const AtomicString& AXLayoutObject::accessKey() const
 {
     Node* node = m_layoutObject->node();
     if (!node)
         return nullAtom;
     if (!node->isElementNode())
         return nullAtom;
     return toElement(node)->getAttribute(accesskeyAttr);
 }
 
-RGBA32 AXLayoutObject::backgroundColor() const
+RGBA32 AXLayoutObject::computeBackgroundColor() const
 {
     if (!getLayoutObject())
         return AXNodeObject::backgroundColor();
 
-    const ComputedStyle* style = getLayoutObject()->style();
-    if (!style || !style->hasBackground())
-        return AXNodeObject::backgroundColor();
+    Color blendedColor = Color::transparent;
+    // Color::blend should be called like this: background.blend(foreground).
+    for (LayoutObject* layoutObject = getLayoutObject(); layoutObject;
+        layoutObject = layoutObject->parent()) {
+        const AXObject* axParent = axObjectCache().getOrCreate(layoutObject);
+        if (axParent && axParent != this) {
+            Color parentColor = axParent->backgroundColor();
+            blendedColor = parentColor.blend(blendedColor);
+            return blendedColor.rgb();
+        }
 
-    Color color = style->visitedDependentColor(CSSPropertyBackgroundColor);
-    return color.rgb();
+        const ComputedStyle* style = layoutObject->style();
+        if (!style || !style->hasBackground())
+            continue;
+
+        Color currentColor = style->visitedDependentColor(CSSPropertyBackgroundColor);
+        blendedColor = currentColor.blend(blendedColor);
+        // Continue blending until we get no transparency.
+        if (!blendedColor.hasAlpha())
+            break;
+    }
+
+    // If we still have some transparency, blend in the document base color.
+    if (blendedColor.hasAlpha()) {
+        FrameView* view = documentFrameView();
+        if (view) {
+            Color documentBaseColor = view->baseBackgroundColor();
+            blendedColor = documentBaseColor.blend(blendedColor);
+        } else {
+            // Default to a white background.
+            blendedColor.blendWithWhite();
+        }
+    }
+
+    return blendedColor.rgb();
 }
 
 RGBA32 AXLayoutObject::color() const
 {
     if (!getLayoutObject() || isColorWell())
         return AXNodeObject::color();
 
     const ComputedStyle* style = getLayoutObject()->style();
     if (!style)
         return AXNodeObject::color();
@@ skipping 813 matching lines @@
 
 Document* AXLayoutObject::getDocument() const
 {
     if (!getLayoutObject())
         return nullptr;
     return &getLayoutObject()->document();
 }
 
 FrameView* AXLayoutObject::documentFrameView() const
 {
-    if (!m_layoutObject)
-        return 0;
+    if (!getLayoutObject())
+        return nullptr;
 
     // this is the LayoutObject's Document's LocalFrame's FrameView
-    return m_layoutObject->document().view();
+    return getLayoutObject()->document().view();
 }
 
 Element* AXLayoutObject::anchorElement() const
 {
     if (!m_layoutObject)
         return 0;
 
     AXObjectCacheImpl& cache = axObjectCache();
     LayoutObject* currLayoutObject;
 
@@ skipping 781 matching lines @@
         if (label && label->layoutObject()) {
             LayoutRect labelRect = axObjectCache().getOrCreate(label)->elementRect();
             result.unite(labelRect);
         }
     }
 
     return result;
 }
 
 } // namespace blink