Separate zeroing pixel data from setting alpha

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

Index: third_party/WebKit/Source/platform/image-decoders/ImageFrame.cpp
diff --git a/third_party/WebKit/Source/platform/image-decoders/ImageFrame.cpp b/third_party/WebKit/Source/platform/image-decoders/ImageFrame.cpp
index af1e07f91fda56196443c9254fd4f3151c1ca6c9..d6eb419669797a89f3ebbc40ffc04508ff0af391 100644
--- a/third_party/WebKit/Source/platform/image-decoders/ImageFrame.cpp
+++ b/third_party/WebKit/Source/platform/image-decoders/ImageFrame.cpp
@@ -79,7 +79,6 @@ void ImageFrame::clearPixelData() {
 
 void ImageFrame::zeroFillPixelData() {
   m_bitmap.eraseARGB(0, 0, 0, 0);
-  m_hasAlpha = true;
 }
 
 bool ImageFrame::copyBitmapData(const ImageFrame& other) {
@@ -109,10 +108,14 @@ bool ImageFrame::allocatePixelData(int newWidth,
   // 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);
 }