Add IsImageElement support for CanvasImageSource.

Currently there is no way to know if a CanvasImageSource comes from
an HTML Image Element, so this CL adds another function to the base
class to differentiate SVGs from Image Elements.

Change-Id: I3978171ba199f372ec685d446215bdfdc83eaa9f
Reviewed-on: https://chromium-review.googlesource.com/c/1301967Reviewed-by: Fernando Serboncini <fserb@chromium.org>
Commit-Queue: David Quiroz Marin <davidqu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#603162}

third_party/blink/renderer/core/html/canvas/canvas_image_source.h

@@ -62,6 +62,7 @@ class CORE_EXPORT CanvasImageSource {
       const SecurityOrigin* destination_security_origin) const = 0;
 
   virtual bool IsCSSImageValue() const { return false; }
+  virtual bool IsImageElement() const { return false; }
   virtual bool IsVideoElement() const { return false; }
   virtual bool IsCanvasElement() const { return false; }
   virtual bool IsSVGSource() const { return false; }

third_party/blink/renderer/core/html/canvas/image_element_base.cc

@@ -40,6 +40,10 @@ bool ImageElementBase::IsSVGSource() const {
   return CachedImage() && CachedImage()->GetImage()->IsSVGImage();
 }
 
+bool ImageElementBase::IsImageElement() const {
+  return CachedImage() && !CachedImage()->GetImage()->IsSVGImage();
+}
+
 scoped_refptr<Image> ImageElementBase::GetSourceImageForCanvas(
     SourceImageStatus* status,
     AccelerationHint,

third_party/blink/renderer/core/html/canvas/image_element_base.h

@@ -47,6 +47,8 @@ class CORE_EXPORT ImageElementBase : public CanvasImageSource,
 
   bool IsSVGSource() const override;
 
+  bool IsImageElement() const override;
+
   bool IsOpaque() const override;
 
   const KURL& SourceURL() const override;