Fix clang static analyzer errors in Gr

Review URL: http://codereview.appspot.com/5433055/


git-svn-id: http://skia.googlecode.com/svn/trunk@2743 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/GrGpuGLShaders.cpp b/src/gpu/GrGpuGLShaders.cpp
index bae699d..7b364e6 100644
--- a/src/gpu/GrGpuGLShaders.cpp
+++ b/src/gpu/GrGpuGLShaders.cpp
@@ -546,7 +546,7 @@
         // down).
         float values[6] = {
             GrScalarToFloat(a),
-            1 / (2.f * values[0]),
+            1 / (2.f * GrScalarToFloat(a)),
             GrScalarToFloat(centerX1),
             GrScalarToFloat(radius0),
             GrScalarToFloat(GrMul(radius0, radius0)),