replace setConfig+allocPixels with single call

BUG=skia:

Review URL: https://codereview.chromium.org/162643002

git-svn-id: http://skia.googlecode.com/svn/trunk@13426 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/tests/FlatDataTest.cpp b/tests/FlatDataTest.cpp
index 36fecf9..4b56fc0 100644
--- a/tests/FlatDataTest.cpp
+++ b/tests/FlatDataTest.cpp
@@ -68,8 +68,7 @@
     // Test SkBitmap
     {
         SkBitmap bm;
-        bm.setConfig(SkBitmap::kARGB_8888_Config, 50, 50);
-        bm.allocPixels();
+        bm.allocN32Pixels(50, 50);
         SkCanvas canvas(bm);
         SkPaint paint;
         paint.setShader(shader);