Bug 1410129 - Restore scoping of RAII class instantation. r=mattwoodrow

MozReview-Commit-ID: 1Eojy6STwfl

--HG--
extra : rebase_source : dd85375a1aedf6166477148a90dbc397c1c4366a

gfx/layers/wr/WebRenderCommandBuilder.cpp

@@ -213,14 +213,15 @@ WebRenderCommandBuilder::CreateWebRenderCommandsFromDisplayList(nsDisplayList* a
       }
     }
 
-    // ensure the scope of ScrollingLayersHelper is maintained
-    ScrollingLayersHelper clip(item, aBuilder, aSc, mClipIdCache, apzEnabled);
+    { // ensure the scope of ScrollingLayersHelper is maintained
+      ScrollingLayersHelper clip(item, aBuilder, aSc, mClipIdCache, apzEnabled);
 
-    // Note: this call to CreateWebRenderCommands can recurse back into
-    // this function if the |item| is a wrapper for a sublist.
-    if (!item->CreateWebRenderCommands(aBuilder, aResources, aSc, mManager,
-                                       aDisplayListBuilder)) {
-      PushItemAsImage(item, aBuilder, aResources, aSc, aDisplayListBuilder);
+      // Note: this call to CreateWebRenderCommands can recurse back into
+      // this function if the |item| is a wrapper for a sublist.
+      if (!item->CreateWebRenderCommands(aBuilder, aResources, aSc, mManager,
+                                         aDisplayListBuilder)) {
+        PushItemAsImage(item, aBuilder, aResources, aSc, aDisplayListBuilder);
+      }
     }
 
     if (apzEnabled) {