Fixed Windows compiler complaints (esp. in debugger)

https://codereview.appspot.com/6497090/



git-svn-id: http://skia.googlecode.com/svn/trunk@5419 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/debugger/QT/SkSettingsWidget.cpp b/debugger/QT/SkSettingsWidget.cpp
index 2519efd..d9268be 100644
--- a/debugger/QT/SkSettingsWidget.cpp
+++ b/debugger/QT/SkSettingsWidget.cpp
@@ -157,6 +157,6 @@
     } else if (scaleFactor > 1) {
         fZoomBox.setText(QString::number(scaleFactor*100).append("%"));
     } else if (scaleFactor < -1) {
-        fZoomBox.setText(QString::number(100 / pow(2, (-scaleFactor - 1))).append("%"));
+        fZoomBox.setText(QString::number(100 / pow(2.0f, (-scaleFactor - 1))).append("%"));
     }
 }