--- a/dom/messagechannel/MessagePortChild.cpp
+++ b/dom/messagechannel/MessagePortChild.cpp
@@ -6,16 +6,21 @@
 #include "MessagePortChild.h"
 #include "MessagePort.h"
 #include "mozilla/dom/MessageEvent.h"
 #include "mozilla/ipc/PBackgroundChild.h"
 
 namespace mozilla {
 namespace dom {
 
+void
+MessagePortChild::ignoreMe()
+{
+}
+
 mozilla::ipc::IPCResult
 MessagePortChild::RecvStopSendingDataConfirmed()
 {
   MOZ_ASSERT(mPort);
   mPort->StopSendingDataConfirmed();
   MOZ_ASSERT(!mPort);
   return IPC_OK();
 }

--- a/dom/messagechannel/MessagePortChild.h
+++ b/dom/messagechannel/MessagePortChild.h
@@ -12,16 +12,18 @@
 namespace mozilla {
 namespace dom {
 
 class MessagePort;
 
 class MessagePortChild final : public PMessagePortChild
 {
 public:
+  virtual void ignoreMe();
+
   NS_INLINE_DECL_REFCOUNTING(MessagePortChild)
 
   MessagePortChild() : mPort(nullptr) {}
 
   void SetPort(MessagePort* aPort)
   {
     mPort = aPort;
   }

--- a/gfx/thebes/gfxFontInfoLoader.cpp
+++ b/gfx/thebes/gfxFontInfoLoader.cpp
@@ -14,16 +14,21 @@ using services::GetObserverService;
 
 #define LOG_FONTINIT(args) MOZ_LOG(gfxPlatform::GetLog(eGfxLog_fontinit), \
                                LogLevel::Debug, args)
 #define LOG_FONTINIT_ENABLED() MOZ_LOG_TEST( \
                                    gfxPlatform::GetLog(eGfxLog_fontinit), \
                                    LogLevel::Debug)
 
 void
+FontInfoData::ignoreMe()
+{
+}
+
+void
 FontInfoData::Load()
 {
     TimeStamp start = TimeStamp::Now();
 
     uint32_t i, n = mFontFamiliesToLoad.Length();
     mLoadStats.families = n;
     for (i = 0; i < n && !mCanceled; i++) {
         // font file memory mapping sometimes causes exceptions - bug 1100949

--- a/gfx/thebes/gfxFontInfoLoader.h
+++ b/gfx/thebes/gfxFontInfoLoader.h
@@ -42,16 +42,18 @@ struct FontFaceData {
 // methods in this class are called on off-main threads so
 // all methods use only static methods or other thread-safe
 // font data access API's. specifically, no use is made of
 // gfxPlatformFontList, gfxFontFamily, gfxFamily or any
 // harfbuzz API methods within FontInfoData subclasses.
 
 class FontInfoData {
 public:
+    virtual void ignoreMe();
+
     NS_INLINE_DECL_THREADSAFE_REFCOUNTING(FontInfoData)
 
     FontInfoData(bool aLoadOtherNames,
                  bool aLoadFaceNames,
                  bool aLoadCmaps) :
         mCanceled(false),
         mLoadOtherNames(aLoadOtherNames),
         mLoadFaceNames(aLoadFaceNames),