Rename SkCodec::kNone to SkCodec::kNoFrame

Add a SK_LEGACY_SKCODEC_NONE_ENUM #define'able to ease transition.

Also rename another internal "kNone" enum in SkWebpCodec.cpp.

The "kNone" name is overloaded:
- include/core/SkImageGenerator.h defines its own kNone.
- include/encode/SkPngEncoder.h defines its own kNone.
- include/private/GrTypesPriv.h defines multiple kNone's.

Bug: skia:
Change-Id: I18c03a74f2f1b0237016e0eef53dcd4478b82609
Reviewed-on: https://skia-review.googlesource.com/146020
Reviewed-by: Derek Sollenberger <djsollen@google.com>
Reviewed-by: Leon Scroggins <scroggo@google.com>
Commit-Queue: Leon Scroggins <scroggo@google.com>
diff --git a/dm/DMSrcSink.cpp b/dm/DMSrcSink.cpp
index 93877c1..57827e0 100644
--- a/dm/DMSrcSink.cpp
+++ b/dm/DMSrcSink.cpp
@@ -501,18 +501,18 @@
 
             // Used to cache a frame that future frames will depend on.
             SkAutoMalloc priorFramePixels;
-            int cachedFrame = SkCodec::kNone;
+            int cachedFrame = SkCodec::kNoFrame;
             for (int i = 0; static_cast<size_t>(i) < frameInfos.size(); i++) {
                 options.fFrameIndex = i;
                 // Check for a prior frame
                 const int reqFrame = frameInfos[i].fRequiredFrame;
-                if (reqFrame != SkCodec::kNone && reqFrame == cachedFrame
+                if (reqFrame != SkCodec::kNoFrame && reqFrame == cachedFrame
                         && priorFramePixels.get()) {
                     // Copy into pixels
                     memcpy(pixels.get(), priorFramePixels.get(), safeSize);
                     options.fPriorFrame = reqFrame;
                 } else {
-                    options.fPriorFrame = SkCodec::kNone;
+                    options.fPriorFrame = SkCodec::kNoFrame;
                 }
                 SkCodec::Result result = codec->getPixels(decodeInfo, pixels.get(),
                                                           rowBytes, &options);