Issue #2364 - use DrawTarget::DrawSurfaceWithShadow to render box shadows on platforms that accelerate it.

gfx/2d/Blur.h

@@ -99,6 +99,16 @@ public:
    */
   Rect* GetDirtyRect();
 
+  /**
+   * Return the spread radius, in pixels.
+   */
+  IntSize GetSpreadRadius() const { return mSpreadRadius; }
+
+  /**
+   * Return the blur radius, in pixels.
+   */
+  IntSize GetBlurRadius() const { return mBlurRadius; }
+
   /**
    * Return the minimum buffer size that should be given to Blur() method.  If
    * zero, the class is not properly setup for blurring.  Note that this
@@ -122,6 +132,7 @@ public:
    * constructor, above.
    */
   static IntSize CalculateBlurRadius(const Point& aStandardDeviation);
+  static Float CalculateBlurSigma(int32_t aBlurRadius);
 
 private: