Correct SourceImageStatus in OffscreenCanvas::getSourceImageForCanvas

third_party/WebKit/Source/core/offscreencanvas/OffscreenCanvas.cpp

 // Copyright 2015 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/offscreencanvas/OffscreenCanvas.h"
 
 #include "core/dom/ExceptionCode.h"
 #include "core/html/canvas/CanvasContextCreationAttributes.h"
 #include "core/html/canvas/CanvasRenderingContext.h"
 #include "core/html/canvas/CanvasRenderingContextFactory.h"
@@ skipping 56 matching lines @@
         return nullptr;
     }
     ImageBitmap* image = m_context->transferToImageBitmap(exceptionState);
     if (!image) {
         // Undocumented exception (not in spec)
         exceptionState.throwDOMException(V8Error, "Out of memory");
     }
     return image;
 }
 
-PassRefPtr<Image> OffscreenCanvas::getSourceImageForCanvas(SourceImageStatus* status, AccelerationHint hint, SnapshotReason reason, const FloatSize&) const
+PassRefPtr<Image> OffscreenCanvas::getSourceImageForCanvas(SourceImageStatus* status, AccelerationHint hint, SnapshotReason reason, const FloatSize& size) const
 {
     if (!m_context) {
         *status = InvalidSourceImageStatus;
         return nullptr;
     }
-    *status = NormalSourceImageStatus;
-    return m_context->getImage(hint, reason);
+    if (!size.width() || !size.height()) {
+        *status = ZeroSizeCanvasSourceImageStatus;
+        return nullptr;
+    }
+    RefPtr<Image> image = m_context->getImage(hint, reason);
+    if (!image) {
+        *status = InvalidSourceImageStatus;
+    } else {
+        *status = NormalSourceImageStatus;
+    }
+    return image.release();
 }
 
 bool OffscreenCanvas::isOpaque() const
 {
     if (!m_context)
         return false;
     return !m_context->creationAttributes().hasAlpha();
 }
 
 CanvasRenderingContext* OffscreenCanvas::getCanvasRenderingContext(ScriptState* scriptState, const String& id, const CanvasContextCreationAttributes& attributes)
@@ skipping 62 matching lines @@
     }
     return m_frameDispatcher.get();
 }
 
 DEFINE_TRACE(OffscreenCanvas)
 {
     visitor->trace(m_context);
 }
 
 } // namespace blink