Fix background blending for some cases where it did not work at all. The fix adds the blendMode par…

Source/core/platform/graphics/ImageBuffer.cpp

Index: Source/core/platform/graphics/ImageBuffer.cpp
diff --git a/Source/core/platform/graphics/ImageBuffer.cpp b/Source/core/platform/graphics/ImageBuffer.cpp
index 86fde9637bf93805800850150773d2a31cea747d..48f2f54951c38fc7cdced7bee47c1be5477d7df3 100644
--- a/Source/core/platform/graphics/ImageBuffer.cpp
+++ b/Source/core/platform/graphics/ImageBuffer.cpp
@@ -254,14 +254,14 @@ void ImageBuffer::draw(GraphicsContext* context, const FloatRect& destRect, cons
 }
 
 void ImageBuffer::drawPattern(GraphicsContext* context, const FloatRect& srcRect, const FloatSize& scale,
-    const FloatPoint& phase, CompositeOperator op, const FloatRect& destRect)
+    const FloatPoint& phase, CompositeOperator op, const FloatRect& destRect, BlendMode blendMode)
 {
     if (!isValid())
         return;
 
     const SkBitmap& bitmap = *m_context->bitmap();
     RefPtr<Image> image = BitmapImage::create(NativeImageSkia::create(drawNeedsCopy(m_context.get(), context) ? deepSkBitmapCopy(bitmap) : bitmap));
-    image->drawPattern(context, srcRect, scale, phase, op, destRect);
+    image->drawPattern(context, srcRect, scale, phase, op, destRect, blendMode);
 }
 
 void ImageBuffer::transformColorSpace(ColorSpace srcColorSpace, ColorSpace dstColorSpace)