From b6f282fb4f2a5bcac2878726617f61b2ea992280 Mon Sep 17 00:00:00 2001
From: Robert O'Callahan <robert@ocallahan.org>
Date: Fri, 9 Dec 2011 22:53:14 +1300
Subject: [PATCH] Bug 705559. Part 4: Speed up AddDependencyOnSource by exiting
 early when we already have the dependency. r=bas

---
 gfx/2d/DrawTargetD2D.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gfx/2d/DrawTargetD2D.cpp b/gfx/2d/DrawTargetD2D.cpp
index 3e75af006fb9..30e77aee09a9 100644
--- a/gfx/2d/DrawTargetD2D.cpp
+++ b/gfx/2d/DrawTargetD2D.cpp
@@ -249,7 +249,7 @@ DrawTargetD2D::Flush()
 void
 DrawTargetD2D::AddDependencyOnSource(SourceSurfaceD2DTarget* aSource)
 {
-  if (aSource->mDrawTarget) {
+  if (aSource->mDrawTarget && !mDependingOnTargets.count(aSource->mDrawTarget)) {
     aSource->mDrawTarget->mDependentTargets.insert(this);
     mDependingOnTargets.insert(aSource->mDrawTarget);
   }