Allow zoom/restore in a zoomed document. It is a regression from an earlier fix.

Source/core/html/ImageDocument.h

Index: Source/core/html/ImageDocument.h
diff --git a/Source/core/html/ImageDocument.h b/Source/core/html/ImageDocument.h
index 896a46261da7f9affb5c064c054959087710a58b..bc68d2d86388f80e08d154dbd6f8ced5ecfec89f 100644
--- a/Source/core/html/ImageDocument.h
+++ b/Source/core/html/ImageDocument.h
@@ -40,10 +40,15 @@ public:
         return adoptRef(new ImageDocument(initializer));
     }
 
+    enum ScaleType {
+        ScaleZoomedDocument,
+        ScaleOnlyUnzoomedDocument
+    };
+
     ImageResource* cachedImage();
     HTMLImageElement* imageElement() const { return m_imageElement.get(); }
 
-    void windowSizeChanged();
+    void windowSizeChanged(ScaleType);
     void imageUpdated();
     void imageClicked(int x, int y);
 
@@ -54,8 +59,8 @@ private:
     virtual void dispose() OVERRIDE;
 
     void createDocumentStructure();
-    void resizeImageToFit();
-    void restoreImageSize();
+    void resizeImageToFit(ScaleType);
+    void restoreImageSize(ScaleType);
     bool imageFitsInWindow() const;
     bool shouldShrinkToFit() const;
     float scale() const;