Minor Windows compiler complaint fixes

http://codereview.appspot.com/5988072/



git-svn-id: http://skia.googlecode.com/svn/trunk@3644 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/GrContext.cpp b/src/gpu/GrContext.cpp
index a87631c..f044909 100644
--- a/src/gpu/GrContext.cpp
+++ b/src/gpu/GrContext.cpp
@@ -2108,7 +2108,8 @@
     SkRect srcRect(rect);
     scale_rect(&srcRect, 1.0f / scaleFactorX, 1.0f / scaleFactorY);
     srcRect.roundOut();
-    scale_rect(&srcRect, scaleFactorX, scaleFactorY);
+    scale_rect(&srcRect, static_cast<float>(scaleFactorX), 
+                         static_cast<float>(scaleFactorY));
     this->setClip(srcRect);
 
     const GrTextureDesc desc = {