Fix warnings on VS2015 x86_64 build

gm/lightingshader.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "gm.h"
 
 #include "SkColorPriv.h"
@@ skipping 20 matching lines @@
         for (int x = 0; x < texSize; ++x) {
             SkScalar locX = (x + 0.5f - texSize/2.0f) / (texSize/2.0f);
             SkScalar locY = (y + 0.5f - texSize/2.0f) / (texSize/2.0f);
             
             SkScalar locZ = locX * locX + locY * locY;
             if (locZ >= 1.0f) {
                 locX = 0.0f;
                 locY = 0.0f;
                 locZ = 0.0f;
             }
-            locZ = sqrt(1.0f - locZ);
+            locZ = sqrtf(1.0f - locZ);
             unsigned char r = static_cast<unsigned char>((0.5f * locX + 0.5f) * 255);
             unsigned char g = static_cast<unsigned char>((-0.5f * locY + 0.5f) * 255);
             unsigned char b = static_cast<unsigned char>((0.5f * locZ + 0.5f) * 255);
             *hemi.getAddr32(x, y) = SkPackARGB32(0xFF, r, g, b);
         }
     }
 
     return hemi;
 }
 
@@ skipping 122 matching lines @@
     SkColor3f               fAmbient;
 
     typedef GM INHERITED;
 };
 
 //////////////////////////////////////////////////////////////////////////////
 
 DEF_GM( return SkNEW(LightingShaderGM); )
 
 }