Hook up CSSPaintValue::image to CSS Paint API callback.

third_party/WebKit/Source/core/css/CSSPaintValue.cpp

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/css/CSSPaintValue.h"
 
 #include "core/css/CSSCustomIdentValue.h"
+#include "core/layout/LayoutObject.h"
 #include "platform/graphics/Image.h"
 #include "wtf/text/StringBuilder.h"
 
 namespace blink {
 
 CSSPaintValue::CSSPaintValue(CSSCustomIdentValue* name)
     : CSSImageGeneratorValue(PaintClass)
     , m_name(name)
+    , m_paintImageGeneratorObserver(new Observer(this))
 {
 }
 
 CSSPaintValue::~CSSPaintValue()
 {
 }
 
 String CSSPaintValue::customCSSText() const
 {
     StringBuilder result;
     result.appendLiteral("paint(");
     result.append(m_name->customCSSText());
     result.append(')');
     return result.toString();
 }
 
 String CSSPaintValue::name() const
 {
     return m_name->value();
 }
 
-PassRefPtr<Image> CSSPaintValue::image(const LayoutObject&, const IntSize&)
+PassRefPtr<Image> CSSPaintValue::image(const LayoutObject& layoutObject, const IntSize& size)
 {
-    // TODO(ikilpatrick): implement.
-    return nullptr;
+    if (!m_generator)
+        m_generator = CSSPaintImageGenerator::create(name(), layoutObject.document(), m_paintImageGeneratorObserver);
+
+    return m_generator->paint(size);
+}
+
+void CSSPaintValue::Observer::paintImageGeneratorReady()
+{
+    m_ownerValue->paintImageGeneratorReady();
+}
+
+void CSSPaintValue::paintImageGeneratorReady()
+{
+    for (const LayoutObject* client : clients().keys()) {
+        const_cast<LayoutObject*>(client)->imageChanged(static_cast<WrappedImagePtr>(this));
+    }
 }
 
 bool CSSPaintValue::equals(const CSSPaintValue& other) const
 {
     return name() == other.name();
 }
 
 DEFINE_TRACE_AFTER_DISPATCH(CSSPaintValue)
 {
     visitor->trace(m_name);
+    visitor->trace(m_generator);
+    visitor->trace(m_paintImageGeneratorObserver);
     CSSImageGeneratorValue::traceAfterDispatch(visitor);
 }
 
 } // namespace blink