Fix build warnings in SkAlphaThresholdFilter

BUG=None
R=bsalomon@google.com

Author: zork@chromium.org

Review URL: https://codereview.chromium.org/101763010

git-svn-id: http://skia.googlecode.com/svn/trunk@12937 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/tests/GLProgramsTest.cpp b/tests/GLProgramsTest.cpp
index a1dbea8..7e55cc7 100644
--- a/tests/GLProgramsTest.cpp
+++ b/tests/GLProgramsTest.cpp
@@ -260,7 +260,7 @@
 
 void forceLinking() {
     SkLightingImageFilter::CreateDistantLitDiffuse(SkPoint3(0,0,0), 0, 0, 0);
-    SkAlphaThresholdFilter::Create(SkRegion(), .5, .5);
+    SkAlphaThresholdFilter::Create(SkRegion(), .5f, .5f);
     SkMagnifierImageFilter mag(SkRect::MakeWH(SK_Scalar1, SK_Scalar1), SK_Scalar1);
     GrConfigConversionEffect::Create(NULL,
                                      false,