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/PDFPrimitivesTest.cpp b/tests/PDFPrimitivesTest.cpp
index b05d4c8..b1d482f 100644
--- a/tests/PDFPrimitivesTest.cpp
+++ b/tests/PDFPrimitivesTest.cpp
@@ -243,8 +243,7 @@
 
 // Create a bitmap that would be very eficiently compressed in a ZIP.
 static void setup_bitmap(SkBitmap* bitmap, int width, int height) {
-    bitmap->setConfig(SkBitmap::kARGB_8888_Config, width, height);
-    bitmap->allocPixels();
+    bitmap->allocN32Pixels(width, height);
     bitmap->eraseColor(SK_ColorWHITE);
 }