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>

2 files changed, 8 insertions, 2 deletions

diff --git a/third_party/gif/SkGifImageReader.cpp b/third_party/gif/SkGifImageReader.cpp
index e76028dac9..76f3edcef0 100644
--- a/third_party/gif/SkGifImageReader.cpp
+++ b/third_party/gif/SkGifImageReader.cpp
@@ -762,11 +762,13 @@ bool SkGifImageReader::parse(SkGifImageReader::SkGIFParseQuery query)
                         isLocalColormapDefined, numColors))
                 {
                     m_firstFrameHasAlpha = true;
+                    m_firstFrameSupportsIndex8 = true;
                 } else {
                     const bool frameIsSubset = xOffset > 0 || yOffset > 0
                             || width < fScreenWidth
                             || height < fScreenHeight;
                     m_firstFrameHasAlpha = frameIsSubset;
+                    m_firstFrameSupportsIndex8 = !frameIsSubset;
                 }
             }
 
diff --git a/third_party/gif/SkGifImageReader.h b/third_party/gif/SkGifImageReader.h
index 49655c23df..f105a1de87 100644
--- a/third_party/gif/SkGifImageReader.h
+++ b/third_party/gif/SkGifImageReader.h
@@ -289,6 +289,7 @@ public:
         , m_streamBuffer(stream)
         , m_parseCompleted(false)
         , m_firstFrameHasAlpha(false)
+        , m_firstFrameSupportsIndex8(false)
     {
     }
 
@@ -366,6 +367,8 @@ public:
 
     bool firstFrameHasAlpha() const { return m_firstFrameHasAlpha; }
 
+    bool firstFrameSupportsIndex8() const { return m_firstFrameSupportsIndex8; }
+
     // Helper function that returns whether an SkGIFFrameContext has transparency.
     // This method is sometimes called before creating one/parsing its color map,
     // so it cannot rely on SkGIFFrameContext::transparentPixel or ::localColorMap().
@@ -407,9 +410,10 @@ private:
     SkStreamBuffer m_streamBuffer;
     bool m_parseCompleted;
 
-    // This value can be computed before we create a SkGIFFrameContext, so we
-    // store it here instead of on m_frames[0].
+    // These values can be computed before we create a SkGIFFrameContext, so we
+    // store them here instead of on m_frames[0].
     bool m_firstFrameHasAlpha;
+    bool m_firstFrameSupportsIndex8;
 };
 
 #endif