Add a ref-counted data holder to ArrayBufferContents

Source/platform/graphics/ImageBuffer.cpp

Index: Source/platform/graphics/ImageBuffer.cpp
diff --git a/Source/platform/graphics/ImageBuffer.cpp b/Source/platform/graphics/ImageBuffer.cpp
index fc8b628f5296cccf1cf002047157c4fc571542a4..b50e80a8eae8f2dd30714175b5ded4d423a20304 100644
--- a/Source/platform/graphics/ImageBuffer.cpp
+++ b/Source/platform/graphics/ImageBuffer.cpp
@@ -281,7 +281,7 @@ bool ImageBuffer::getImageData(Multiply multiplied, const IntRect& rect, WTF::Ar
         return false;
 
     if (!isSurfaceValid()) {
-        WTF::ArrayBufferContents result(rect.width() * rect.height(), 4, WTF::ArrayBufferContents::ZeroInitialize);
+        WTF::ArrayBufferContents result(rect.width() * rect.height(), 4, WTF::ArrayBufferContents::NotShared, WTF::ArrayBufferContents::ZeroInitialize);
         result.transfer(contents);
         return true;
     }
@@ -293,6 +293,7 @@ bool ImageBuffer::getImageData(Multiply multiplied, const IntRect& rect, WTF::Ar
         || rect.maxY() > m_surface->size().height();
     WTF::ArrayBufferContents result(
         rect.width() * rect.height(), 4,
+        WTF::ArrayBufferContents::NotShared,
         hasStrayArea
         ? WTF::ArrayBufferContents::ZeroInitialize
         : WTF::ArrayBufferContents::DontInitialize);