Revert of Refactoring: Remove dead code in DeferredImageDecoder::createFrameAtIndex

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 80 matching lines @@
     return m_actualDecoder ? m_actualDecoder->filenameExtension() : m_filenameExtension;
 }
 
 PassRefPtr<SkImage> DeferredImageDecoder::createFrameAtIndex(size_t index)
 {
     if (m_frameGenerator && m_frameGenerator->decodeFailed())
         return nullptr;
 
     prepareLazyDecodedFrames();
 
-    DCHECK(index < m_frameData.size());
-    DeferredFrameData* frameData = &m_frameData[index];
-    if (m_actualDecoder)
-        frameData->m_frameBytes = m_actualDecoder->frameBytesAtIndex(index);
-    else
-        frameData->m_frameBytes = m_size.area() * sizeof(ImageFrame::PixelData);
-    // ImageFrameGenerator has the latest known alpha state. There will be a
-    // performance boost if this frame is opaque.
-    DCHECK(m_frameGenerator);
-    return createFrameImageAtIndex(index, !m_frameGenerator->hasAlpha(index));
+    if (index < m_frameData.size()) {
+        DeferredFrameData* frameData = &m_frameData[index];
+        if (m_actualDecoder)
+            frameData->m_frameBytes = m_actualDecoder->frameBytesAtIndex(index);
+        else
+            frameData->m_frameBytes = m_size.area() * sizeof(ImageFrame::PixelData);
+        // ImageFrameGenerator has the latest known alpha state. There will be a
+        // performance boost if this frame is opaque.
+        DCHECK(m_frameGenerator);
+        return createFrameImageAtIndex(index, !m_frameGenerator->hasAlpha(index));
+    }
+
+    if (!m_actualDecoder || m_actualDecoder->failed())
+        return nullptr;
+
+    ImageFrame* frame = m_actualDecoder->frameBufferAtIndex(index);
+    if (!frame || frame->getStatus() == ImageFrame::FrameEmpty)
+        return nullptr;
+
+    return fromSkSp(SkImage::MakeFromBitmap(frame->bitmap()));
 }
 
 PassRefPtr<SharedBuffer> DeferredImageDecoder::data()
 {
     if (!m_rwBuffer)
         return nullptr;
     RefPtr<SkROBuffer> roBuffer = adoptRef(m_rwBuffer->newRBufferSnapshot());
     RefPtr<SharedBuffer> sharedBuffer = SharedBuffer::create();
     SkROBuffer::Iter it(roBuffer.get());
     do {
@@ skipping 208 matching lines @@
 }
 
 } // namespace blink
 
 namespace WTF {
 template<> struct VectorTraits<blink::DeferredFrameData> : public SimpleClassVectorTraits<blink::DeferredFrameData> {
     STATIC_ONLY(VectorTraits);
     static const bool canInitializeWithMemset = false; // Not all DeferredFrameData members initialize to 0.
 };
 }