Separate zeroing pixel data from setting alpha

third_party/WebKit/Source/platform/image-decoders/ImageFrame.cpp

 /*
  * Copyright (C) 2006 Apple Computer, Inc.  All rights reserved.
  * Copyright (C) 2008, 2009 Google, Inc.
  *
  * 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
@@ skipping 61 matching lines @@
   m_bitmap.reset();
   m_status = FrameEmpty;
   // NOTE: Do not reset other members here; clearFrameBufferCache()
   // calls this to free the bitmap data, but other functions like
   // initFrameBuffer() and frameComplete() may still need to read
   // other metadata out of this frame later.
 }
 
 void ImageFrame::zeroFillPixelData() {
   m_bitmap.eraseARGB(0, 0, 0, 0);
-  m_hasAlpha = true;
 }
 
 bool ImageFrame::copyBitmapData(const ImageFrame& other) {
   DCHECK_NE(this, &other);
   m_hasAlpha = other.m_hasAlpha;
   m_bitmap.reset();
   return other.m_bitmap.copyTo(&m_bitmap, other.m_bitmap.colorType());
 }
 
 bool ImageFrame::takeBitmapDataIfWritable(ImageFrame* other) {
   DCHECK(other);
   DCHECK_EQ(FrameComplete, other->m_status);
   DCHECK_EQ(FrameEmpty, m_status);
   DCHECK_NE(this, other);
   if (other->m_bitmap.isImmutable())
     return false;
   m_hasAlpha = other->m_hasAlpha;
   m_bitmap.reset();
   m_bitmap.swap(other->m_bitmap);
   other->m_status = FrameEmpty;
   return true;
 }
 
 bool ImageFrame::allocatePixelData(int newWidth,
                                    int newHeight,
                                    sk_sp<SkColorSpace> colorSpace) {
   // allocatePixelData() should only be called once.
   DCHECK(!width() && !height());
 
-  m_bitmap.setInfo(SkImageInfo::MakeN32(
-      newWidth, newHeight,
-      m_premultiplyAlpha ? kPremul_SkAlphaType : kUnpremul_SkAlphaType,
-      std::move(colorSpace)));
+  SkAlphaType alphaType = kOpaque_SkAlphaType;
+  if (m_hasAlpha) {
+    alphaType =
+        m_premultiplyAlpha ? kPremul_SkAlphaType : kUnpremul_SkAlphaType;
+  }
+
+  m_bitmap.setInfo(SkImageInfo::MakeN32(newWidth, newHeight, alphaType,
+                                        std::move(colorSpace)));
   return m_bitmap.tryAllocPixels(m_allocator, 0);
 }
 
 bool ImageFrame::hasAlpha() const {
   return m_hasAlpha;
 }
 
 sk_sp<SkImage> ImageFrame::finalizePixelsAndGetImage() {
   DCHECK_EQ(FrameComplete, m_status);
   m_bitmap.setImmutable();
@@ skipping 76 matching lines @@
   // If the frame is not fully loaded, there will be transparent pixels,
   // so we can't tell skia we're opaque, even for image types that logically
   // always are (e.g. jpeg).
   if (!m_hasAlpha && m_status == FrameComplete)
     return kOpaque_SkAlphaType;
 
   return m_premultiplyAlpha ? kPremul_SkAlphaType : kUnpremul_SkAlphaType;
 }
 
 }  // namespace blink