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/images/SkDecodingImageGenerator.cpp b/src/images/SkDecodingImageGenerator.cpp
index b3924a7..5b842ab 100644
--- a/src/images/SkDecodingImageGenerator.cpp
+++ b/src/images/SkDecodingImageGenerator.cpp
@@ -242,7 +242,7 @@
         if (kIndex_8_SkColorType == bitmap.colorType()) {
             // We don't support kIndex8 because we don't support
             // colortables in this workflow.
-            info.fColorType = kN32_SkColorType;
+            info.fColorType = kPMColor_SkColorType;
         }
     } else {
         if (!bitmap.canCopyTo(opts.fRequestedColorType)) {