Remove image decoder down sampling

Source/core/platform/image-decoders/gif/GIFImageDecoder.cpp

Index: Source/core/platform/image-decoders/gif/GIFImageDecoder.cpp
diff --git a/Source/core/platform/image-decoders/gif/GIFImageDecoder.cpp b/Source/core/platform/image-decoders/gif/GIFImageDecoder.cpp
index d785aec0341c6f5f782e4ffe3b97e4b74b001224..fa2929b08925ef12eb890311bfd2da7337bb3aae 100644
--- a/Source/core/platform/image-decoders/gif/GIFImageDecoder.cpp
+++ b/Source/core/platform/image-decoders/gif/GIFImageDecoder.cpp
@@ -67,11 +67,7 @@ bool GIFImageDecoder::setSize(unsigned width, unsigned height)
     if (ImageDecoder::isSizeAvailable() && size() == IntSize(width, height))
         return true;
 
-    if (!ImageDecoder::setSize(width, height))
-        return false;
-
-    prepareScaleDataIfNecessary();
-    return true;
+    return ImageDecoder::setSize(width, height);

[Peter Kasting, 2013/05/20 23:04:24]

It seems like we no longer need to override setSize() at all in this class,
since the return at top here doesn't really change the outcome of anything.

[Noel Gordon, 2013/05/21 04:24:03]

Yes I had wondered about that, and I wanted confirmation that I could remove it
in the GIF case ...

 }
 
 size_t GIFImageDecoder::frameCount()
@@ -204,10 +200,10 @@ bool GIFImageDecoder::haveDecodedRow(unsigned frameIndex, const Vector<unsigned
     // that width == (size().width() - frameContext->xOffset), so
     // we must ensure we don't run off the end of either the source data or the
     // row's X-coordinates.
-    int xBegin = upperBoundScaledX(frameContext->xOffset);
-    int yBegin = upperBoundScaledY(frameContext->yOffset + rowNumber);
-    int xEnd = lowerBoundScaledX(std::min(static_cast<int>(frameContext->xOffset + width), size().width()) - 1, xBegin + 1) + 1;
-    int yEnd = lowerBoundScaledY(std::min(static_cast<int>(frameContext->yOffset + rowNumber + repeatCount), size().height()) - 1, yBegin + 1) + 1;
+    int xBegin = frameContext->xOffset;
+    int yBegin = frameContext->yOffset + rowNumber;
+    int xEnd = std::min(static_cast<int>(frameContext->xOffset + width), size().width());
+    int yEnd = std::min(static_cast<int>(frameContext->yOffset + rowNumber + repeatCount), size().height());
     if (rowBuffer.isEmpty() || (xBegin < 0) || (yBegin < 0) || (xEnd <= xBegin) || (yEnd <= yBegin))
         return true;
 
@@ -232,7 +228,7 @@ bool GIFImageDecoder::haveDecodedRow(unsigned frameIndex, const Vector<unsigned
     ImageFrame::PixelData* currentAddress = buffer.getAddr(xBegin, yBegin);
     // Write one row's worth of data into the frame.  
     for (int x = xBegin; x < xEnd; ++x) {
-        const unsigned char sourceValue = rowBuffer[(m_scaled ? m_scaledColumns[x] : x) - frameContext->xOffset];
+        const unsigned char sourceValue = rowBuffer[x - frameContext->xOffset];
         if ((!frameContext->isTransparent || (sourceValue != frameContext->tpixel)) && (sourceValue < colorMapSize)) {
             const size_t colorIndex = static_cast<size_t>(sourceValue) * 3;
             buffer.setRGBA(currentAddress, colorMap[colorIndex], colorMap[colorIndex + 1], colorMap[colorIndex + 2], 255);
@@ -273,7 +269,7 @@ bool GIFImageDecoder::frameComplete(unsigned frameIndex, unsigned frameDuration,
     if (!m_currentBufferSawAlpha) {
         // The whole frame was non-transparent, so it's possible that the entire
         // resulting buffer was non-transparent, and we can setHasAlpha(false).
-        if (buffer.originalFrameRect().contains(IntRect(IntPoint(), scaledSize())))
+        if (buffer.originalFrameRect().contains(IntRect(IntPoint(), size())))
             buffer.setHasAlpha(false);
         else if (frameIndex) {
             // Tricky case.  This frame does not have alpha only if everywhere
@@ -364,15 +360,11 @@ bool GIFImageDecoder::initFrameBuffer(unsigned frameIndex)
         frameRect.setHeight(size().height() - frameContext->yOffset);
 
     ImageFrame* const buffer = &m_frameBufferCache[frameIndex];
-    int left = upperBoundScaledX(frameRect.x());
-    int right = lowerBoundScaledX(frameRect.maxX(), left);
-    int top = upperBoundScaledY(frameRect.y());
-    int bottom = lowerBoundScaledY(frameRect.maxY(), top);
-    buffer->setOriginalFrameRect(IntRect(left, top, right - left, bottom - top));
+    buffer->setOriginalFrameRect(frameRect);
     
     if (!frameIndex) {
         // This is the first frame, so we're not relying on any previous data.
-        if (!buffer->setSize(scaledSize().width(), scaledSize().height()))
+        if (!buffer->setSize(size().width(), size().height()))
             return setFailed();
     } else {
         // The starting state for this frame depends on the previous frame's
@@ -399,8 +391,8 @@ bool GIFImageDecoder::initFrameBuffer(unsigned frameIndex)
             // We want to clear the previous frame to transparent, without
             // affecting pixels in the image outside of the frame.
             const IntRect& prevRect = prevBuffer->originalFrameRect();
-            const IntSize& bufferSize = scaledSize();
-            if (!frameIndex || prevRect.contains(IntRect(IntPoint(), scaledSize()))) {
+            const IntSize& bufferSize = size();
+            if (!frameIndex || prevRect.contains(IntRect(IntPoint(), size()))) {
                 // Clearing the first frame, or a frame the size of the whole
                 // image, results in a completely empty image.
                 if (!buffer->setSize(bufferSize.width(), bufferSize.height()))