Fix ImageDecoder::frameIsCompleteAtIndex - fully received instead of decoded.

third_party/WebKit/Source/platform/image-decoders/bmp/BMPImageReader.cpp

Index: third_party/WebKit/Source/platform/image-decoders/bmp/BMPImageReader.cpp
diff --git a/third_party/WebKit/Source/platform/image-decoders/bmp/BMPImageReader.cpp b/third_party/WebKit/Source/platform/image-decoders/bmp/BMPImageReader.cpp
index 7e10d1d10a1a57d2d6724d62ce89a52d1bbad3c1..43736b09c37d33dd9fc6f34bc848d4e08537c173 100644
--- a/third_party/WebKit/Source/platform/image-decoders/bmp/BMPImageReader.cpp
+++ b/third_party/WebKit/Source/platform/image-decoders/bmp/BMPImageReader.cpp
@@ -79,6 +79,7 @@ BMPImageReader::BMPImageReader(ImageDecoder* parent, size_t decodedAndHeaderOffs
     , m_needToProcessColorTable(false)
     , m_seenNonZeroAlphaPixel(false)
     , m_seenZeroAlphaPixel(false)
+    , m_hasPixelsWithAlpha(false)
     , m_isInICO(isInICO)
     , m_decodingAndMask(false)
 {
@@ -119,10 +120,6 @@ bool BMPImageReader::decodeBMP(bool onlySize)
         if (!m_buffer->setSize(m_parent->size().width(), m_parent->size().height()))
             return m_parent->setFailed(); // Unable to allocate.
         m_buffer->setStatus(ImageFrame::FramePartial);

[scroggo_chromium, 2016/05/16 20:32:08]

Previously, this set the alpha to false for a partially decoded BMP. Please add
a test for this behavior change.

-        // setSize() calls eraseARGB(), which resets the alpha flag, so we force
-        // it back to false here.  We'll set it true below in all cases where
-        // these 0s could actually show through.
-        m_buffer->setHasAlpha(false);
 
         // For BMPs, the frame always fills the entire image.
         m_buffer->setOriginalFrameRect(IntRect(IntPoint(), m_parent->size()));
@@ -151,6 +148,7 @@ bool BMPImageReader::decodeBMP(bool onlySize)
         return false;
 
     // Done!
+    m_buffer->setHasAlpha(m_hasPixelsWithAlpha);
     m_buffer->setStatus(ImageFrame::FrameComplete);
     return true;
 }
@@ -610,7 +608,7 @@ BMPImageReader::ProcessingResult BMPImageReader::processRLEData()
             case 0:  // Magic token: EOL
                 // Skip any remaining pixels in this row.
                 if (m_coord.x() < m_parent->size().width())
-                    m_buffer->setHasAlpha(true);
+                    m_hasPixelsWithAlpha = true;
                 moveBufferToNextRow();
 
                 m_decodedOffset += 2;
@@ -619,7 +617,7 @@ BMPImageReader::ProcessingResult BMPImageReader::processRLEData()
             case 1:  // Magic token: EOF
                 // Skip any remaining pixels in the image.
                 if ((m_coord.x() < m_parent->size().width()) || (m_isTopDown ? (m_coord.y() < (m_parent->size().height() - 1)) : (m_coord.y() > 0)))
-                    m_buffer->setHasAlpha(true);
+                    m_hasPixelsWithAlpha = true;
                 // There's no need to move |m_coord| here to trigger the caller
                 // to call setPixelsChanged().  If the only thing that's changed
                 // is the alpha state, that will be properly written into the
@@ -637,7 +635,7 @@ BMPImageReader::ProcessingResult BMPImageReader::processRLEData()
                 const uint8_t dx = readUint8(2);
                 const uint8_t dy = readUint8(3);
                 if (dx || dy)
-                    m_buffer->setHasAlpha(true);
+                    m_hasPixelsWithAlpha = true;
                 if (((m_coord.x() + dx) > m_parent->size().width()) || pastEndOfImage(dy))
                     return Failure;
 
@@ -749,7 +747,7 @@ BMPImageReader::ProcessingResult BMPImageReader::processNonRLEData(bool inRLE, i
                         // web will not be doing a lot of inverting.
                         if (colorIndex) {
                             setRGBA(0, 0, 0, 0);
-                            m_buffer->setHasAlpha(true);
+                            m_hasPixelsWithAlpha = true;
                         } else
                             m_coord.move(1, 0);
                     } else {
@@ -785,8 +783,9 @@ BMPImageReader::ProcessingResult BMPImageReader::processNonRLEData(bool inRLE, i
                     if (m_seenZeroAlphaPixel) {
                         m_buffer->zeroFillPixelData();
                         m_seenZeroAlphaPixel = false;
-                    } else if (alpha != 255)
-                        m_buffer->setHasAlpha(true);
+                    } else if (alpha != 255) {
+                        m_hasPixelsWithAlpha = true;
+                    }
                 }
 
                 setRGBA(getComponent(pixel, 0), getComponent(pixel, 1),