GIF decoding to Index8, unit tests and misusing unit test as benchmark

third_party/WebKit/Source/platform/graphics/DecodingImageGenerator.cpp

Index: third_party/WebKit/Source/platform/graphics/DecodingImageGenerator.cpp
diff --git a/third_party/WebKit/Source/platform/graphics/DecodingImageGenerator.cpp b/third_party/WebKit/Source/platform/graphics/DecodingImageGenerator.cpp
index a1adcce004f065ad73110d3e77733144419bfd66..de91b558ba91bdc9d57d62dd89d0b17578500fd5 100644
--- a/third_party/WebKit/Source/platform/graphics/DecodingImageGenerator.cpp
+++ b/third_party/WebKit/Source/platform/graphics/DecodingImageGenerator.cpp
@@ -71,14 +71,15 @@ bool DecodingImageGenerator::onGetPixels(const SkImageInfo& info, void* pixels,
     if (info.width() != getInfo().width() || info.height() != getInfo().height())
         return false;
 
-    if (info.colorType() != getInfo().colorType()) {
+    // if colorType declared in getInfo() fails, Skia would fetch N32 version
+    if (info.colorType() != getInfo().colorType() && info.colorType() != kN32_SkColorType) {
         // ImageFrame may have changed the owning SkBitmap to kOpaque_SkAlphaType after sniffing the encoded data, so if we see a request
         // for opaque, that is ok even if our initial alphatype was not opaque.
         return false;
     }
 
     PlatformInstrumentation::willDecodeLazyPixelRef(m_generationId);
-    bool decoded = m_frameGenerator->decodeAndScale(getInfo(), m_frameIndex, pixels, rowBytes);
+    bool decoded = m_frameGenerator->decodeAndScale(info, m_frameIndex, pixels, rowBytes, ctable, ctableCount);
     PlatformInstrumentation::didDecodeLazyPixelRef();
 
     return decoded;
@@ -116,7 +117,9 @@ SkImageGenerator* DecodingImageGenerator::create(SkData* data)
         return 0;
 
     const IntSize size = decoder->size();
-    const SkImageInfo info = SkImageInfo::MakeN32Premul(size.width(), size.height());
+    const SkImageInfo info = decoder->canDecodeTo(0, ImageFrame::Index8)
+        ? SkImageInfo::Make(size.width(), size.height(), kIndex_8_SkColorType, kPremul_SkAlphaType)
+        : SkImageInfo::MakeN32Premul(size.width(), size.height());
 
     RefPtr<ImageFrameGenerator> frame = ImageFrameGenerator::create(SkISize::Make(size.width(), size.height()), buffer, true, false);
     if (!frame)
@@ -125,5 +128,14 @@ SkImageGenerator* DecodingImageGenerator::create(SkData* data)
     return new DecodingImageGenerator(frame, info, 0);
 }
 
+SkColorType DecodingImageGenerator::onGetColorType()
+{
+    // GIFDecoder: generator info is Index8 when constructed. but after downloading data this could
+    // change - it could turn out that some frames can be decoded only to N32.
+    if (m_frameGenerator->canDecodeTo(m_frameIndex, kIndex_8_SkColorType))
+        return kIndex_8_SkColorType;
+    return kN32_SkColorType;
+}
+
 } // namespace blink