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

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

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 195 matching lines @@
 
 void DeferredImageDecoder::activateLazyDecoding()
 {
     if (m_frameGenerator)
         return;
     m_size = m_actualDecoder->size();
     m_filenameExtension = m_actualDecoder->filenameExtension();
     m_hasColorProfile = m_actualDecoder->hasColorProfile();
     const bool isSingleFrame = m_actualDecoder->repetitionCount() == cAnimationNone || (m_allDataReceived && m_actualDecoder->frameCount() == 1u);
     m_frameGenerator = ImageFrameGenerator::create(SkISize::Make(m_actualDecoder->decodedSize().width(), m_actualDecoder->decodedSize().height()), m_data, m_allDataReceived, !isSingleFrame);
+    // GIF images support Index8 decoding: other decoders do not.
+    m_frameGenerator->setDecoderCanDecodeToIndex8(m_filenameExtension == "gif");
 }
 
 void DeferredImageDecoder::prepareLazyDecodedFrames()
 {
     if (!s_enabled
         || !m_actualDecoder
         || !m_actualDecoder->isSizeAvailable()
         || m_actualDecoder->filenameExtension() == "ico")
         return;
 
@@ skipping 27 matching lines @@
     }
 }
 
 // Creates an SkImage that is backed by SkDiscardablePixelRef.
 PassRefPtr<SkImage> DeferredImageDecoder::createImage(size_t index, bool knownToBeOpaque) const
 {
     SkISize decodedSize = m_frameGenerator->getFullSize();
     ASSERT(decodedSize.width() > 0);
     ASSERT(decodedSize.height() > 0);
 
-    const SkImageInfo info = SkImageInfo::MakeN32(decodedSize.width(), decodedSize.height(),
-        knownToBeOpaque ? kOpaque_SkAlphaType : kPremul_SkAlphaType);
+    const SkImageInfo info = m_frameGenerator->canDecodeTo(index, kIndex_8_SkColorType)
+        ? SkImageInfo::Make(decodedSize.width(), decodedSize.height(), kIndex_8_SkColorType,
+            knownToBeOpaque ? kOpaque_SkAlphaType : kPremul_SkAlphaType)
+        : SkImageInfo::MakeN32(decodedSize.width(), decodedSize.height(),
+            knownToBeOpaque ? kOpaque_SkAlphaType : kPremul_SkAlphaType);
 
     DecodingImageGenerator* generator = new DecodingImageGenerator(m_frameGenerator, info, index);
     RefPtr<SkImage> image = adoptRef(SkImage::NewFromGenerator(generator));
     if (!image)
         return nullptr;
 
     generator->setGenerationId(image->uniqueID());
     return image.release();
 }
 
 bool DeferredImageDecoder::hotSpot(IntPoint& hotSpot) const
 {
     // TODO: Implement.
     return m_actualDecoder ? m_actualDecoder->hotSpot(hotSpot) : false;
 }
 
 } // namespace blink