--- a/dom/plugins/base/nsNPAPIPluginInstance.cpp
+++ b/dom/plugins/base/nsNPAPIPluginInstance.cpp
@@ -54,17 +54,16 @@ nsNPAPIPluginInstance::nsNPAPIPluginInst
   , mUsesDOMForCursor(false)
   , mInPluginInitCall(false)
   , mPlugin(nullptr)
   , mMIMEType(nullptr)
   , mOwner(nullptr)
 #ifdef XP_MACOSX
   , mCurrentPluginEvent(nullptr)
 #endif
-  , mHaveJavaC2PJSObjectQuirk(false)
   , mCachedParamLength(0)
   , mCachedParamNames(nullptr)
   , mCachedParamValues(nullptr)
   , mMuted(false)
 {
   mNPP.pdata = nullptr;
   mNPP.ndata = this;
 

--- a/dom/plugins/base/nsNPAPIPluginInstance.h
+++ b/dom/plugins/base/nsNPAPIPluginInstance.h
@@ -293,19 +293,16 @@ private:
   // non-null during a HandleEvent call
   void* mCurrentPluginEvent;
 #endif
 
   // Timestamp for the last time this plugin was stopped.
   // This is only valid when the plugin is actually stopped!
   mozilla::TimeStamp mStopTime;
 
-  // is this instance Java and affected by bug 750480?
-  bool mHaveJavaC2PJSObjectQuirk;
-
   static uint32_t gInUnsafePluginCalls;
 
   // The arrays can only be released when the plugin instance is destroyed,
   // because the plugin, in in-process mode, might keep a reference to them.
   uint32_t mCachedParamLength;
   char **mCachedParamNames;
   char **mCachedParamValues;