Bug 981393 - Crash the child process if we get invalid Compositable updates. r=nical

gfx/layers/ipc/ImageBridgeParent.cpp

@@ -86,7 +86,9 @@ ImageBridgeParent::RecvUpdate(const EditArray& aEdits, EditReplyArray* aReply)
 
   EditReplyVector replyv;
   for (EditArray::index_type i = 0; i < aEdits.Length(); ++i) {
-    ReceiveCompositableUpdate(aEdits[i], replyv);
+    if (!ReceiveCompositableUpdate(aEdits[i], replyv)) {
+      return false;
+    }
   }
 
   aReply->SetCapacity(replyv.size());

gfx/layers/ipc/LayerTransactionParent.cpp

@@ -495,8 +495,10 @@ LayerTransactionParent::RecvUpdate(const InfallibleTArray<Edit>& cset,
       break;
     }
     case Edit::TCompositableOperation: {
-      ReceiveCompositableUpdate(edit.get_CompositableOperation(),
-                                replyv);
+      if (!ReceiveCompositableUpdate(edit.get_CompositableOperation(),
+                                replyv)) {
+        return false;
+      }
       break;
     }
     case Edit::TOpAttachCompositable: {