From 0749ba9357d9b89d3abf10cc845d422a6888e64f Mon Sep 17 00:00:00 2001
From: Julian Seward <jseward@acm.org>
Date: Tue, 16 Aug 2016 11:05:08 +0200
Subject: [PATCH] Bug 1289098 - Fixes to avoid Valgrind false positives with
 gcc-5.4 -O2 builds.  r=dbaron.

--HG--
extra : rebase_source : 489e0686b650f329c41bc5d2c2504ac308b9541d
---
 layout/style/nsStyleContext.cpp | 5 ++++-
 layout/style/nsStyleStruct.cpp  | 5 ++++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/layout/style/nsStyleContext.cpp b/layout/style/nsStyleContext.cpp
index 626cef0d47ce..b6cf5aaa3e2c 100644
--- a/layout/style/nsStyleContext.cpp
+++ b/layout/style/nsStyleContext.cpp
@@ -1148,7 +1148,10 @@ nsStyleContext::CalcStyleDifferenceInternal(StyleContextLike* aNewContext,
       const nsStyleOutline *thisVisOutline = thisVis->StyleOutline();
       const nsStyleOutline *otherVisOutline = otherVis->StyleOutline();
       bool haveColor;
-      nscolor thisColor, otherColor;
+      // Dummy initialisations to keep Valgrind/Memcheck happy.
+      // See bug 1289098 comment 1.
+      nscolor thisColor = NS_RGBA(0, 0, 0, 0);
+      nscolor otherColor = NS_RGBA(0, 0, 0, 0);
       if (thisVisOutline->GetOutlineInitialColor() !=
             otherVisOutline->GetOutlineInitialColor() ||
           (haveColor = thisVisOutline->GetOutlineColor(thisColor)) !=
diff --git a/layout/style/nsStyleStruct.cpp b/layout/style/nsStyleStruct.cpp
index b699c7729ddd..0f742845b7d8 100644
--- a/layout/style/nsStyleStruct.cpp
+++ b/layout/style/nsStyleStruct.cpp
@@ -3698,7 +3698,10 @@ nsStyleTextReset::CalcDifference(const nsStyleTextReset& aNewData) const
   }
 
   // Repaint for decoration color changes
-  nscolor decColor, otherDecColor;
+  // Dummy initialisations to keep Valgrind/Memcheck happy.
+  // See bug 1289098 comment 1.
+  nscolor decColor = NS_RGBA(0, 0, 0, 0);
+  nscolor otherDecColor = NS_RGBA(0, 0, 0, 0);
   bool isFG, otherIsFG;
   GetDecorationColor(decColor, isFG);
   aNewData.GetDecorationColor(otherDecColor, otherIsFG);