Bug 938687 - Check the value of PR_Close() and issue warning when it is not PR_SUCCESS. r=bsmedberg

dom/ipc/TabParent.cpp

@@ -179,7 +179,11 @@ private:
 
         MOZ_ASSERT(mFD);
 
-        PR_Close(mFD);
+        PRStatus prrc;
+        prrc = PR_Close(mFD);
+        if (prrc != PR_SUCCESS) {
+          NS_ERROR("PR_Close() failed.");
+        }
         mFD = nullptr;
     }
 };