From a593c1be08dda0b9555c6bdf1678ba3cd9b10b87 Mon Sep 17 00:00:00 2001
From: Lee Salzman <lsalzman@mozilla.com>
Date: Sun, 24 Sep 2017 19:11:17 -0400
Subject: [PATCH] Bug 1402585 - don't error when ShmSegmentReader reads empty
 segments. r=gankro

MozReview-Commit-ID: B18t0mrEIDm
---
 gfx/layers/wr/IpcResourceUpdateQueue.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/gfx/layers/wr/IpcResourceUpdateQueue.cpp b/gfx/layers/wr/IpcResourceUpdateQueue.cpp
index b0a0a05af530..19169e6355a5 100644
--- a/gfx/layers/wr/IpcResourceUpdateQueue.cpp
+++ b/gfx/layers/wr/IpcResourceUpdateQueue.cpp
@@ -182,6 +182,10 @@ ShmSegmentsReader::ReadLarge(const layers::OffsetRange& aRange, wr::Vec_u8& aInt
 bool
 ShmSegmentsReader::Read(const layers::OffsetRange& aRange, wr::Vec_u8& aInto)
 {
+  if (aRange.length() == 0) {
+    return true;
+  }
+
   if (aRange.source() != 0) {
     return ReadLarge(aRange, aInto);
   }