From e3912d560bb83aaffde2729da8810ffa1b161d5d Mon Sep 17 00:00:00 2001
From: Urvang Joshi <urvang@google.com>
Date: Tue, 19 Apr 2016 16:13:45 -0700
Subject: [PATCH] WebPAnimEncoder: Restore canvas before evaluating blending
 possibility.

Without this, the canvas may have been modified in-between two
GenerateCandidate() calls.

Change-Id: I0364a269caabdf282c30a8fa3c61896f0247342e
---
 src/mux/anim_encode.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/mux/anim_encode.c b/src/mux/anim_encode.c
index 44f63efb..79aaa87c 100644
--- a/src/mux/anim_encode.c
+++ b/src/mux/anim_encode.c
@@ -873,10 +873,14 @@ static WebPEncodingError GenerateCandidates(
   WebPPicture* const curr_canvas = &enc->curr_canvas_copy_;
   const WebPPicture* const prev_canvas =
       is_dispose_none ? &enc->prev_canvas_ : &enc->prev_canvas_disposed_;
-  const int use_blending_ll =
+  int use_blending_ll;
+  int use_blending_lossy;
+
+  CopyCurrentCanvas(enc);
+  use_blending_ll =
       !is_key_frame &&
       IsLosslessBlendingPossible(prev_canvas, curr_canvas, &params->rect_ll_);
-  const int use_blending_lossy =
+  use_blending_lossy =
       !is_key_frame &&
       IsLossyBlendingPossible(prev_canvas, curr_canvas, &params->rect_lossy_,
                               config_lossy->quality);