Revert of Rename kPMColor_SkColorType to kN32_SkColorType. (https://codereview.chromium.org/227433009/)

Reason for revert:
Chrome's side of define changes not easy to figure out quickly. Reverting this for DEPS roll for now.

Original issue's description:
> Rename kPMColor_SkColorType to kN32_SkColorType.
>
> The new name better represents what this flag means.
>
> BUG=skia:2384
>
> Committed: http://code.google.com/p/skia/source/detail?r=14117

R=reed@google.com, scroggo@google.com
TBR=reed@google.com, scroggo@google.com
NOTREECHECKS=true
NOTRY=true
BUG=skia:2384

Author: bensong@google.com

Review URL: https://codereview.chromium.org/234833003

git-svn-id: http://skia.googlecode.com/svn/trunk@14149 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/effects/gradients/SkGradientShader.cpp b/src/effects/gradients/SkGradientShader.cpp
index 2ebb9c7..b1fa560 100644
--- a/src/effects/gradients/SkGradientShader.cpp
+++ b/src/effects/gradients/SkGradientShader.cpp
@@ -517,7 +517,7 @@
         info.fWidth = kCache32Count;
         info.fHeight = 4;   // for our 4 dither rows
         info.fAlphaType = kPremul_SkAlphaType;
-        info.fColorType = kN32_SkColorType;
+        info.fColorType = kPMColor_SkColorType;
 
         if (NULL == fCache32PixelRef) {
             fCache32PixelRef = SkMallocPixelRef::NewAllocate(info, 0, NULL);