use some helper Make functions to initialize SkImageInfo

BUG=
R=halcanary@google.com, scroggo@google.com

Author: reed@google.com

Review URL: https://codereview.chromium.org/137993012

git-svn-id: http://skia.googlecode.com/svn/trunk@13081 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/core/SkImageFilterUtils.cpp b/src/core/SkImageFilterUtils.cpp
index 92fe67e..204f38d 100644
--- a/src/core/SkImageFilterUtils.cpp
+++ b/src/core/SkImageFilterUtils.cpp
@@ -15,12 +15,7 @@
 #include "SkGr.h"
 
 bool SkImageFilterUtils::WrapTexture(GrTexture* texture, int width, int height, SkBitmap* result) {
-    SkImageInfo info = {
-        width,
-        height,
-        kPMColor_SkColorType,
-        kPremul_SkAlphaType,
-    };
+    SkImageInfo info = SkImageInfo::MakeN32Premul(width, height);
     result->setConfig(info);
     result->setPixelRef(SkNEW_ARGS(SkGrPixelRef, (info, texture)))->unref();
     return true;