From 42d8ee76ab35b64d9c2e13722f6da71d41e75dbb Mon Sep 17 00:00:00 2001
From: Andrew Osmond <aosmond@mozilla.com>
Date: Fri, 10 Feb 2017 08:33:11 -0500
Subject: [PATCH] Bug 1290293 - Part 2f. Assert there is no frame on the finish
 decoding error path. r=tnikkel

---
 image/Decoder.cpp               | 7 ++++++-
 image/decoders/nsICODecoder.cpp | 2 ++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/image/Decoder.cpp b/image/Decoder.cpp
index d6633e63f371..da24766c069f 100644
--- a/image/Decoder.cpp
+++ b/image/Decoder.cpp
@@ -380,7 +380,12 @@ Decoder::AllocateFrameInternal(uint32_t aFrameNum,
 nsresult Decoder::InitInternal() { return NS_OK; }
 nsresult Decoder::BeforeFinishInternal() { return NS_OK; }
 nsresult Decoder::FinishInternal() { return NS_OK; }
-nsresult Decoder::FinishWithErrorInternal() { return NS_OK; }
+
+nsresult Decoder::FinishWithErrorInternal()
+{
+  MOZ_ASSERT(!mInFrame);
+  return NS_OK;
+}
 
 /*
  * Progress Notifications
diff --git a/image/decoders/nsICODecoder.cpp b/image/decoders/nsICODecoder.cpp
index 8791d67396ec..f56f800a0f95 100644
--- a/image/decoders/nsICODecoder.cpp
+++ b/image/decoders/nsICODecoder.cpp
@@ -79,6 +79,8 @@ nsICODecoder::FinishInternal()
 nsresult
 nsICODecoder::FinishWithErrorInternal()
 {
+  // No need to assert !mInFrame here because this condition is enforced by
+  // mContainedDecoder.
   return GetFinalStateFromContainedDecoder();
 }