From c371700a13d19f0ac62063ca0229d3e36e4cd4dd Mon Sep 17 00:00:00 2001
From: George Wright <george@mozilla.com>
Date: Fri, 6 Jun 2014 14:26:21 -0400
Subject: [PATCH] Bug 913805 - Hold a lock on the RasterImage in ScaleRequest
 so that the srcFrame doesn't go away if we need to discard images to free up
 memory r=seth

---
 image/src/RasterImage.cpp | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/image/src/RasterImage.cpp b/image/src/RasterImage.cpp
index d2ebf5c03cd7..6d19e49ca270 100644
--- a/image/src/RasterImage.cpp
+++ b/image/src/RasterImage.cpp
@@ -211,13 +211,16 @@ public:
 
     bool success = false;
     if (!dstLocked) {
+      // We need to hold a lock onto the RasterImage object itself so that
+      // it (and its associated imgFrames) aren't marked as discardable.
+      bool imgLocked = NS_SUCCEEDED(image->LockImage());
       bool srcLocked = NS_SUCCEEDED(srcFrame->LockImageData());
       srcSurface = srcFrame->GetSurface();
 
       dstLocked = NS_SUCCEEDED(dstFrame->LockImageData());
       dstSurface = dstFrame->GetSurface();
 
-      success = srcLocked && dstLocked && srcSurface && dstSurface;
+      success = imgLocked && srcLocked && dstLocked && srcSurface && dstSurface;
 
       if (success) {
         srcData = srcFrame->GetImageData();
@@ -253,6 +256,7 @@ public:
       if (DiscardingEnabled())
         dstFrame->SetDiscardable();
       success = NS_SUCCEEDED(dstFrame->UnlockImageData());
+      success = success && NS_SUCCEEDED(image->UnlockImage());
 
       dstLocked = false;
       srcData = nullptr;