Making LayoutUnit conversions to Float type explicit

Source/core/html/ImageDocument.cpp

Index: Source/core/html/ImageDocument.cpp
diff --git a/Source/core/html/ImageDocument.cpp b/Source/core/html/ImageDocument.cpp
index 193cbab3c9c63b704fa9eae7c33ac516f59d6d63..2782a6d71b09006be3fb1740f419a40c3ca63fe0 100644
--- a/Source/core/html/ImageDocument.cpp
+++ b/Source/core/html/ImageDocument.cpp
@@ -227,8 +227,8 @@ float ImageDocument::scale() const
     LayoutSize imageSize = m_imageElement->cachedImage()->imageSizeForRenderer(m_imageElement->renderer(), pageZoomFactor(this));
     LayoutSize windowSize = LayoutSize(view->width(), view->height());
 
-    float widthScale = (float)windowSize.width() / imageSize.width();
-    float heightScale = (float)windowSize.height() / imageSize.height();
+    float widthScale = windowSize.width().toFloat() / imageSize.width().toFloat();
+    float heightScale = windowSize.height().toFloat() / imageSize.height().toFloat();
 
     return min(widthScale, heightScale);
 }