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/src/android/SkAnimatedImage.cpp b/src/android/SkAnimatedImage.cpp
index 6bbea6b..d03040c 100644
--- a/src/android/SkAnimatedImage.cpp
+++ b/src/android/SkAnimatedImage.cpp
@@ -96,7 +96,7 @@
 }
 
 SkAnimatedImage::Frame::Frame()
-    : fIndex(SkCodec::kNone)
+    : fIndex(SkCodec::kNoFrame)
 {}
 
 bool SkAnimatedImage::Frame::init(const SkImageInfo& info, OnInit onInit) {
@@ -140,7 +140,7 @@
     fFinished = false;
     fRepetitionsCompleted = 0;
     if (fDisplayFrame.fIndex != 0) {
-        fDisplayFrame.fIndex = SkCodec::kNone;
+        fDisplayFrame.fIndex = SkCodec::kNoFrame;
         this->decodeNextFrame();
     }
 }
@@ -193,7 +193,7 @@
         animationEnded = true;
         if (0 == frameToDecode) {
             // Static image. This is okay.
-            frameInfo.fRequiredFrame = SkCodec::kNone;
+            frameInfo.fRequiredFrame = SkCodec::kNoFrame;
             frameInfo.fAlphaType = fCodec->getInfo().alphaType();
             frameInfo.fDisposalMethod = SkCodecAnimation::DisposalMethod::kKeep;
             // These fields won't be read.
@@ -233,12 +233,12 @@
     // entire dependency chain.
     SkCodec::Options options;
     options.fFrameIndex = frameToDecode;
-    if (frameInfo.fRequiredFrame == SkCodec::kNone) {
+    if (frameInfo.fRequiredFrame == SkCodec::kNoFrame) {
         if (is_restore_previous(frameInfo.fDisposalMethod)) {
             // frameToDecode will be discarded immediately after drawing, so
             // do not overwrite a frame which could possibly be used in the
             // future.
-            if (fDecodingFrame.fIndex != SkCodec::kNone &&
+            if (fDecodingFrame.fIndex != SkCodec::kNoFrame &&
                     !is_restore_previous(fDecodingFrame.fDisposalMethod)) {
                 using std::swap;
                 swap(fDecodingFrame, fRestoreFrame);
@@ -246,7 +246,8 @@
         }
     } else {
         auto validPriorFrame = [&frameInfo, &frameToDecode](const Frame& frame) {
-            if (SkCodec::kNone == frame.fIndex || is_restore_previous(frame.fDisposalMethod)) {
+            if (SkCodec::kNoFrame == frame.fIndex ||
+                    is_restore_previous(frame.fDisposalMethod)) {
                 return false;
             }
 
diff --git a/src/codec/SkCodec.cpp b/src/codec/SkCodec.cpp
index 8bfaae8..5564e89 100644
--- a/src/codec/SkCodec.cpp
+++ b/src/codec/SkCodec.cpp
@@ -280,8 +280,8 @@
     }
 
     const int requiredFrame = frame->getRequiredFrame();
-    if (requiredFrame != kNone) {
-        if (options.fPriorFrame != kNone) {
+    if (requiredFrame != kNoFrame) {
+        if (options.fPriorFrame != kNoFrame) {
             // Check for a valid frame as a starting point. Alternatively, we could
             // treat an invalid frame as not providing one, but rejecting it will
             // make it easier to catch the mistake.
@@ -728,7 +728,7 @@
 }
 
 static bool independent(const SkFrame& frame) {
-    return frame.getRequiredFrame() == SkCodec::kNone;
+    return frame.getRequiredFrame() == SkCodec::kNoFrame;
 }
 
 static bool restore_bg(const SkFrame& frame) {
@@ -743,7 +743,7 @@
     const int i = frame->frameId();
     if (0 == i) {
         frame->setHasAlpha(reportsAlpha || frameRect != screenRect);
-        frame->setRequiredFrame(SkCodec::kNone);
+        frame->setRequiredFrame(SkCodec::kNoFrame);
         return;
     }
 
@@ -751,7 +751,7 @@
     const bool blendWithPrevFrame = frame->getBlend() == SkCodecAnimation::Blend::kPriorFrame;
     if ((!reportsAlpha || !blendWithPrevFrame) && frameRect == screenRect) {
         frame->setHasAlpha(reportsAlpha);
-        frame->setRequiredFrame(SkCodec::kNone);
+        frame->setRequiredFrame(SkCodec::kNoFrame);
         return;
     }
 
@@ -760,7 +760,7 @@
         const int prevId = prevFrame->frameId();
         if (0 == prevId) {
             frame->setHasAlpha(true);
-            frame->setRequiredFrame(SkCodec::kNone);
+            frame->setRequiredFrame(SkCodec::kNoFrame);
             return;
         }
 
@@ -773,7 +773,7 @@
     if (clearPrevFrame) {
         if (prevFrameRect == screenRect || independent(*prevFrame)) {
             frame->setHasAlpha(true);
-            frame->setRequiredFrame(SkCodec::kNone);
+            frame->setRequiredFrame(SkCodec::kNoFrame);
             return;
         }
     }
@@ -790,8 +790,8 @@
 
     while (frameRect.contains(prevFrameRect)) {
         const int prevRequiredFrame = prevFrame->getRequiredFrame();
-        if (prevRequiredFrame == SkCodec::kNone) {
-            frame->setRequiredFrame(SkCodec::kNone);
+        if (prevRequiredFrame == SkCodec::kNoFrame) {
+            frame->setRequiredFrame(SkCodec::kNoFrame);
             frame->setHasAlpha(true);
             return;
         }
@@ -803,7 +803,7 @@
     if (restore_bg(*prevFrame)) {
         frame->setHasAlpha(true);
         if (prevFrameRect == screenRect || independent(*prevFrame)) {
-            frame->setRequiredFrame(SkCodec::kNone);
+            frame->setRequiredFrame(SkCodec::kNoFrame);
         } else {
             // Note: As above, frame could still be independent, e.g. if
             // prevFrame covers its required frame and that frame is
diff --git a/src/codec/SkGifCodec.cpp b/src/codec/SkGifCodec.cpp
index 036ee0b..3ac5ed3 100644
--- a/src/codec/SkGifCodec.cpp
+++ b/src/codec/SkGifCodec.cpp
@@ -343,7 +343,7 @@
         // (or it is already filled for us), so we report rowsDecoded to be the full
         // height.
         bool filledBackground = false;
-        if (frameContext->getRequiredFrame() == kNone) {
+        if (frameContext->getRequiredFrame() == kNoFrame) {
             // We may need to clear to transparent for one of the following reasons:
             // - The frameRect does not cover the full bounds. haveDecodedRow will
             //   only draw inside the frameRect, so we need to clear the rest.
diff --git a/src/codec/SkWebpCodec.cpp b/src/codec/SkWebpCodec.cpp
index 0d12dad..a9c0c32 100644
--- a/src/codec/SkWebpCodec.cpp
+++ b/src/codec/SkWebpCodec.cpp
@@ -435,7 +435,7 @@
     SkAssertResult(WebPDemuxGetFrame(fDemux, index + 1, &frame));
 
     const bool independent = index == 0 ? true :
-            (fFrameHolder.frame(index)->getRequiredFrame() == kNone);
+            (fFrameHolder.frame(index)->getRequiredFrame() == kNoFrame);
     // Get the frameRect.  libwebp will have already signaled an error if this is not fully
     // contained by the canvas.
     auto frameRect = SkIRect::MakeXYWH(frame.x_offset, frame.y_offset, frame.width, frame.height);
@@ -545,7 +545,7 @@
 
     // Choose the step when we will perform premultiplication.
     enum {
-        kNone,
+        kNoPremul,
         kBlendLine,
         kColorXform,
         kLibwebp,
@@ -553,7 +553,7 @@
     auto choose_premul_step = [&]() {
         if (!frame.has_alpha) {
             // None necessary.
-            return kNone;
+            return kNoPremul;
         }
         if (blendWithPrevFrame) {
             // Premultiply in blend_line, in a linear space.
@@ -562,7 +562,7 @@
         if (dstInfo.alphaType() != kPremul_SkAlphaType) {
             // No blending is necessary, so we only need to premultiply if the
             // client requested it.
-            return kNone;
+            return kNoPremul;
         }
         if (this->colorXform()) {
             // Premultiply in the colorXform, in a linear space.