1 files changed, 11 insertions, 3 deletions
diff --git a/image/SourceBuffer.cpp b/image/SourceBuffer.cpp
index de0719d45..de066e29f 100644
--- a/image/SourceBuffer.cpp
+++ b/image/SourceBuffer.cpp
@@ -451,10 +451,18 @@ SourceBuffer::AppendFromInputStream(nsIInputStream* aInputStream,
   uint32_t bytesRead;
   nsresult rv = aInputStream->ReadSegments(AppendToSourceBuffer, this,
                                            aCount, &bytesRead);
-  if (!NS_WARN_IF(NS_FAILED(rv))) {
-    MOZ_ASSERT(bytesRead == aCount,
-               "AppendToSourceBuffer should consume everything");
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  if (bytesRead == 0) {
+    // The loading of the image has been canceled.
+    return NS_ERROR_FAILURE;
   }
+
+  MOZ_ASSERT(bytesRead == aCount,
+             "AppendToSourceBuffer should consume everything");
+
   return rv;
 }