Bug 718440. Add more sampler labels to various places. r=bgirard

This shows the problems described in bug 710068.

layout/base/nsLayoutUtils.cpp

@@ -116,6 +116,8 @@
 #include "nsXULPopupManager.h"
 #endif
 
+#include "sampler.h"
+
 using namespace mozilla;
 using namespace mozilla::layers;
 using namespace mozilla::dom;
@@ -3630,6 +3632,7 @@ nsLayoutUtils::DrawBackgroundImage(nsRenderingContext* aRenderingContext,
                                    const nsRect&       aDirty,
                                    PRUint32            aImageFlags)
 {
+  SAMPLE_LABEL("layout", "nsLayoutUtils::DrawBackgroundImage");
   return DrawImageInternal(aRenderingContext, aImage, aGraphicsFilter,
                            aDest, aFill, aAnchor, aDirty,
                            aImageSize, aImageFlags);