Revert "Remove support for decoding to kIndex_8"

This reverts commit 742a3e298fda669006147e4a305bab8452369b1f.

Reason for revert: Breaking Android roll:
frameworks/base/core/jni/android/graphics/BitmapFactory.cpp:453:18: error: no member named 'fColorPtr' in 'SkAndroidCodec::AndroidOptions'
    codecOptions.fColorPtr = colorPtr;
    ~~~~~~~~~~~~ ^
frameworks/base/core/jni/android/graphics/BitmapFactory.cpp:454:18: error: no member named 'fColorCount' in 'SkAndroidCodec::AndroidOptions'
    codecOptions.fColorCount = colorCount;
    ~~~~~~~~~~~~ ^

Original change's description:
> Remove support for decoding to kIndex_8
> 
> Fix up callsites, and remove tests that no longer make sense.
> 
> Bug: skia:6828
> Change-Id: I2548c4b7528b7b1be7412563156f27b52c9d4295
> Reviewed-on: https://skia-review.googlesource.com/21664
> Reviewed-by: Derek Sollenberger <djsollen@google.com>
> Commit-Queue: Leon Scroggins <scroggo@google.com>

TBR=djsollen@google.com,scroggo@google.com

Change-Id: I1bc669441f250690884e75a9a61427fdf75c6907
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: skia:6828
Reviewed-on: https://skia-review.googlesource.com/22120
Reviewed-by: Leon Scroggins <scroggo@google.com>
Commit-Queue: Leon Scroggins <scroggo@google.com>
diff --git a/src/codec/SkCodecImageGenerator.cpp b/src/codec/SkCodecImageGenerator.cpp
index 57f7fb8..20d547a 100644
--- a/src/codec/SkCodecImageGenerator.cpp
+++ b/src/codec/SkCodecImageGenerator.cpp
@@ -44,7 +44,8 @@
                                         const Options& opts) {
     SkCodec::Options codecOpts;
     codecOpts.fPremulBehavior = opts.fBehavior;
-    SkCodec::Result result = fCodec->getPixels(info, pixels, rowBytes, &codecOpts);
+    SkCodec::Result result = fCodec->getPixels(info, pixels, rowBytes, &codecOpts, nullptr,
+                                               nullptr);
     switch (result) {
         case SkCodec::kSuccess:
         case SkCodec::kIncompleteInput: