Bug 800838 - Guard against invalid NPP when unscheduling plugin timers on Android r=blassey

dom/plugins/base/nsNPAPIPluginInstance.cpp

@@ -151,6 +151,8 @@ private:
   Mutex mLock;
 };
 
+static std::map<NPP, nsNPAPIPluginInstance*> sPluginNPPMap;
+
 #endif
 
 using namespace mozilla;
@@ -190,12 +192,20 @@ nsNPAPIPluginInstance::nsNPAPIPluginInstance()
   mNPP.ndata = this;
 
   PLUGIN_LOG(PLUGIN_LOG_BASIC, ("nsNPAPIPluginInstance ctor: this=%p\n",this));
+
+#ifdef MOZ_WIDGET_ANDROID
+  sPluginNPPMap[&mNPP] = this;
+#endif
 }
 
 nsNPAPIPluginInstance::~nsNPAPIPluginInstance()
 {
   PLUGIN_LOG(PLUGIN_LOG_BASIC, ("nsNPAPIPluginInstance dtor: this=%p\n",this));
 
+#ifdef MOZ_WIDGET_ANDROID
+  sPluginNPPMap.erase(&mNPP);
+#endif
+
   if (mMIMEType) {
     PR_Free((void *)mMIMEType);
     mMIMEType = nullptr;
@@ -1052,6 +1062,17 @@ void nsNPAPIPluginInstance::SetInverted(bool aInverted)
   mInverted = aInverted;
 }
 
+nsNPAPIPluginInstance* nsNPAPIPluginInstance::GetFromNPP(NPP npp)
+{
+  std::map<NPP, nsNPAPIPluginInstance*>::iterator it;
+
+  it = sPluginNPPMap.find(npp);
+  if (it == sPluginNPPMap.end())
+    return nullptr;
+
+  return it->second;
+}
+
 #endif
 
 nsresult nsNPAPIPluginInstance::GetDrawingModel(int32_t* aModel)