--- a/gfx/layers/client/ContentClient.cpp
+++ b/gfx/layers/client/ContentClient.cpp
@@ -347,17 +347,17 @@ ContentClientRemoteBuffer::GetUpdatedReg
   if (mIsNewBuffer || aDidSelfCopy) {
     // A buffer reallocation clears both buffers. The front buffer has all the
     // content by now, but the back buffer is still clear. Here, in effect, we
     // are saying to copy all of the pixels of the front buffer to the back.
     // Also when we self-copied in the buffer, the buffer space
     // changes and some changed buffer content isn't reflected in the
     // draw or invalidate region (on purpose!).  When this happens, we
     // need to read back the entire buffer too.
-    updatedRegion = aVisibleRegion;
+    updatedRegion = aVisibleRegion.GetBounds();
     mIsNewBuffer = false;
   } else {
     updatedRegion = aRegionToDraw;
   }
 
   NS_ASSERTION(BufferRect().Contains(aRegionToDraw.GetBounds()),
                "Update outside of buffer rect!");
   MOZ_ASSERT(mTextureClient, "should have a back buffer by now");