RN: Adjust Image Blur on Android

Summary:
Adjusts the behavior of `blurRadius` for `Image` on Android so that it behaves more closely to other platforms (web and iOS).

Changelog:
[Android][Changed] - Effect of `blurRadius` now more closely matches other platforms.

Reviewed By: shergin

Differential Revision: D22118680

fbshipit-source-id: c6d14aef29b4a086e43badfa78407bfa07f9fee2

Author: yungsters

ReactAndroid/src/main/java/com/facebook/react/views/image/ReactImageView.java

@@ -275,11 +275,12 @@ public void onFailure(String id, Throwable throwable) {
   }
 
   public void setBlurRadius(float blurRadius) {
-    int pixelBlurRadius = (int) PixelUtil.toPixelFromDIP(blurRadius);
+    // Divide `blurRadius` by 2 to more closely match other platforms.
+    int pixelBlurRadius = (int) PixelUtil.toPixelFromDIP(blurRadius) / 2;
     if (pixelBlurRadius == 0) {
       mIterativeBoxBlurPostProcessor = null;
     } else {
-      mIterativeBoxBlurPostProcessor = new IterativeBoxBlurPostProcessor(pixelBlurRadius);
+      mIterativeBoxBlurPostProcessor = new IterativeBoxBlurPostProcessor(2, pixelBlurRadius);
     }
     mIsDirty = true;
   }