Avoid absoluteImageURL() creating data URLs for canvas by default.

Source/core/rendering/HitTestResult.h

Index: Source/core/rendering/HitTestResult.h
diff --git a/Source/core/rendering/HitTestResult.h b/Source/core/rendering/HitTestResult.h
index 84e50f9a3ca8f3d697eadd432780a16b62701f1f..43e19aff4fc0652f0b186014edf3d46a23770388 100644
--- a/Source/core/rendering/HitTestResult.h
+++ b/Source/core/rendering/HitTestResult.h
@@ -106,6 +106,9 @@ public:
     Image* image() const;
     IntRect imageRect() const;
     KURL absoluteImageURL() const;
+    // This variant of absoluteImageURL will also convert <canvas> elements
+    // to huge image data URLs (very expensive).
+    KURL absoluteImageURLIncludingCanvasDataURL() const;
     KURL absoluteMediaURL() const;
     KURL absoluteLinkURL() const;
     String textContent() const;
@@ -132,6 +135,7 @@ public:
     Node* targetNode() const { return innerNode(); }
 
 private:
+    KURL absoluteImageURLInternal(bool allowCanvas) const;
     NodeSet& mutableRectBasedTestResult(); // See above.
     HTMLMediaElement* mediaElement() const;