add SkBitmap::installPixelRef()

BUG=
R=scroggo@google.com

Review URL: https://codereview.chromium.org/129423002

git-svn-id: http://skia.googlecode.com/svn/trunk@13055 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/tests/PixelRefTest.cpp b/tests/PixelRefTest.cpp
index e0ffd7a..3486898 100644
--- a/tests/PixelRefTest.cpp
+++ b/tests/PixelRefTest.cpp
@@ -51,7 +51,7 @@
 }  // namespace
 
 DEF_TEST(PixelRef_GenIDChange, r) {
-    SkImageInfo info = { 10, 10, kPMColor_SkColorType, kPremul_SkAlphaType };
+    SkImageInfo info = SkImageInfo::MakePMPremul(10, 10);
 
     SkAutoTUnref<SkPixelRef> pixelRef(SkMallocPixelRef::NewAllocate(info, 0, NULL));