--- a/gfx/layers/apz/src/AsyncPanZoomController.cpp
+++ b/gfx/layers/apz/src/AsyncPanZoomController.cpp
@@ -405,17 +405,17 @@ GetFrameTime() {
   if (sFrameTime.IsNull()) {
     return TimeStamp::Now();
   }
   return sFrameTime;
 }
 
 class MOZ_STACK_CLASS StateChangeNotificationBlocker {
 public:
-  StateChangeNotificationBlocker(AsyncPanZoomController* aApzc)
+  explicit StateChangeNotificationBlocker(AsyncPanZoomController* aApzc)
     : mApzc(aApzc)
   {
     ReentrantMonitorAutoEnter lock(mApzc->mMonitor);
     mInitialState = mApzc->mState;
     mApzc->mNotificationBlockers++;
   }
 
   ~StateChangeNotificationBlocker()

--- a/gfx/layers/ipc/ThreadSafeRefcountingWithMainThreadDestruction.h
+++ b/gfx/layers/ipc/ThreadSafeRefcountingWithMainThreadDestruction.h
@@ -36,17 +36,17 @@ struct HelperForMainThreadDestruction
     MOZ_ASSERT(NS_IsMainThread());
   }
 };
 
 template<typename T>
 struct DeleteOnMainThreadTask: public nsRunnable
 {
   T* mToDelete;
-  DeleteOnMainThreadTask(T* aToDelete) : mToDelete(aToDelete) {}
+  explicit DeleteOnMainThreadTask(T* aToDelete) : mToDelete(aToDelete) {}
   NS_IMETHOD Run() {
     MOZ_ASSERT(NS_IsMainThread());
     mToDelete->DeleteToBeCalledOnMainThread();
     return NS_OK;
   }
 };
 
 } // namespace layers
@@ -82,9 +82,9 @@ public:                                 
     return count;                                                             \
   }                                                                           \
 protected:                                                                    \
   ::mozilla::ThreadSafeAutoRefCnt mRefCnt;                                    \
 private:                                                                      \
   ::mozilla::layers::HelperForMainThreadDestruction mHelperForMainThreadDestruction; \
 public:
 
-#endif
\ No newline at end of file
+#endif