Have Node::document() return a reference instead of a pointer

Source/core/html/ImageDocument.cpp

Index: Source/core/html/ImageDocument.cpp
diff --git a/Source/core/html/ImageDocument.cpp b/Source/core/html/ImageDocument.cpp
index 57a97d0e703fc75fc28df85d3a9e7cf22a28dfbd..70c13611a6dcfd6310a75e3735e53eb34adf8112 100644
--- a/Source/core/html/ImageDocument.cpp
+++ b/Source/core/html/ImageDocument.cpp
@@ -202,7 +202,7 @@ void ImageDocument::createDocumentStructure()
 
 float ImageDocument::scale() const
 {
-    if (!m_imageElement || m_imageElement->document() != this)
+    if (!m_imageElement || &m_imageElement->document() != this)
         return 1.0f;
 
     FrameView* view = frame()->view();
@@ -220,7 +220,7 @@ float ImageDocument::scale() const
 
 void ImageDocument::resizeImageToFit()
 {
-    if (!m_imageElement || m_imageElement->document() != this || pageZoomFactor(this) > 1)
+    if (!m_imageElement || &m_imageElement->document() != this || pageZoomFactor(this) > 1)
         return;
 
     LayoutSize imageSize = m_imageElement->cachedImage()->imageSizeForRenderer(m_imageElement->renderer(), pageZoomFactor(this));
@@ -275,7 +275,7 @@ void ImageDocument::imageUpdated()
 
 void ImageDocument::restoreImageSize()
 {
-    if (!m_imageElement || !m_imageSizeIsKnown || m_imageElement->document() != this || pageZoomFactor(this) < 1)
+    if (!m_imageElement || !m_imageSizeIsKnown || &m_imageElement->document() != this || pageZoomFactor(this) < 1)
         return;
 
     LayoutSize imageSize = m_imageElement->cachedImage()->imageSizeForRenderer(m_imageElement->renderer(), 1.0f);
@@ -292,7 +292,7 @@ void ImageDocument::restoreImageSize()
 
 bool ImageDocument::imageFitsInWindow() const
 {
-    if (!m_imageElement || m_imageElement->document() != this)
+    if (!m_imageElement || &m_imageElement->document() != this)
         return true;
 
     FrameView* view = frame()->view();
@@ -307,7 +307,7 @@ bool ImageDocument::imageFitsInWindow() const
 
 void ImageDocument::windowSizeChanged()
 {
-    if (!m_imageElement || !m_imageSizeIsKnown || m_imageElement->document() != this)
+    if (!m_imageElement || !m_imageSizeIsKnown || &m_imageElement->document() != this)
         return;
 
     bool fitsInWindow = imageFitsInWindow();