From ee8e0b9c30b293353f4e0dcae6d6f9a287148639 Mon Sep 17 00:00:00 2001
From: Botond Ballo <botond@mozilla.com>
Date: Wed, 25 May 2016 13:16:25 -0400
Subject: [PATCH] Bug 1273227 - Fix an assertion in TextureClient::Unlock().
 r=nical

MozReview-Commit-ID: JwWPe4F0NCq

--HG--
extra : rebase_source : 82262bd0a1ca7a0aa32e7007578b5b00e8139f0f
---
 gfx/layers/client/TextureClient.cpp | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/gfx/layers/client/TextureClient.cpp b/gfx/layers/client/TextureClient.cpp
index 125ba09df9e8..b6b9584ab352 100644
--- a/gfx/layers/client/TextureClient.cpp
+++ b/gfx/layers/client/TextureClient.cpp
@@ -1043,13 +1043,17 @@ TextureClient::SetRemoveFromCompositableWaiter(AsyncTransactionWaiter* aWaiter)
 already_AddRefed<gfx::DataSourceSurface>
 TextureClient::GetAsSurface()
 {
-  Lock(OpenMode::OPEN_READ);
+  if (!Lock(OpenMode::OPEN_READ)) {
+    return nullptr;
+  }
   RefPtr<gfx::DataSourceSurface> data;
-  RefPtr<gfx::DrawTarget> dt = BorrowDrawTarget();
-  if (dt) {
-    RefPtr<gfx::SourceSurface> surf = dt->Snapshot();
-    if (surf) {
-      data = surf->GetDataSurface();
+  {  // scope so that the DrawTarget is destroyed before Unlock()
+    RefPtr<gfx::DrawTarget> dt = BorrowDrawTarget();
+    if (dt) {
+      RefPtr<gfx::SourceSurface> surf = dt->Snapshot();
+      if (surf) {
+        data = surf->GetDataSurface();
+      }
     }
   }
   Unlock();