Allow renderer to get object in browser for arbitrary times.

Now, when creating a remote object in renderer, the browser will
reference the corresponding object by storing it in a strong map. And
when the remote object in renderer is GCed, the corresponding object
will be dereferenced in browser.

browser/atom/objects_registry.coffee

@@ -1,44 +1,58 @@
 IDWeakMap = require 'id_weak_map'
 
-globalStore = {}
-globalMap = new IDWeakMap
+class ObjectsStore
+  @stores = {}
 
-addObjectToWeakMap = (obj) ->
-  id = globalMap.add obj
+  constructor: ->
+    @nextId = 0
+    @objects = []
+
+  getNextId: ->
+    ++@nextId
+
+  add: (obj) ->
+    id = @getNextId()
+    @objects[id] = obj
+    id
+
+  has: (id) ->
+    @objects[id]?
+
+  remove: (id) ->
+    delete @objects[id]
+
+  get: (id) ->
+    throw new Error("Invalid key #{id} for ObjectsStore") unless @has id
+    @objects[id]
+
+  @forRenderView: (process_id, routing_id) ->
+    key = "#{process_id}_#{routing_id}"
+    @stores[key] = new ObjectsStore unless @stores[key]?
+    @stores[key]
+
+objectsWeakMap = new IDWeakMap
+objectsWeakMap.add = (obj) ->
+  id = IDWeakMap::add.call this, obj
   Object.defineProperty obj, 'id',
     enumerable: true, writable: false, value: id
   id
 
-getStoreForRenderView = (process_id, routing_id) ->
-  key = "#{process_id}_#{routing_id}"
-  globalStore[key] = {} unless globalStore[key]?
-  globalStore[key]
-
 process.on 'ATOM_BROWSER_INTERNAL_NEW', (obj) ->
-  # For objects created in browser scripts, keep a weak reference here.
-  addObjectToWeakMap obj
+  # It's possible that user created a object in browser side and then want to
+  # get it in renderer via remote.getObject. So we must add every native object
+  # created in browser to the weak map.
+  objectsWeakMap.add obj
 
 exports.add = (process_id, routing_id, obj) ->
-  # Some native types may already been added to globalMap, in that case we
+  # Some native types may already been added to objectsWeakMap, in that case we
   # don't add it twice.
-  if obj.id?
-    id = obj.id
-  else
-    id = addObjectToWeakMap obj
+  objectsWeakMap.add obj unless obj.id?
 
-  store = getStoreForRenderView process_id, routing_id
-
-  # It's possible that a render view may want to get the same remote object
-  # twice, since we only allow one reference of one object per render view,
-  # we throw when the object is already referenced.
-  throw new Error("Object #{id} is already referenced") if store[id]?
-
-  store[id] = obj
-  id
+  store = ObjectsStore.forRenderView process_id, routing_id
+  store.add obj
 
 exports.get = (id) ->
-  globalMap.get id
+  objectsWeakMap.get id
 
-exports.remove = (process_id, routing_id, id) ->
-  store = getStoreForRenderView process_id, routing_id
-  delete store[id]
+exports.remove = (process_id, routing_id, storeId) ->
+  ObjectsStore.forRenderView(process_id, routing_id).remove storeId

browser/atom/rpc_server.coffee

@@ -13,7 +13,8 @@ class PlainObject
       @members.push new PlainObject(process_id, routing_id, el) for el in value
     else if @type is 'object' or @type is 'function'
       @name = value.constructor.name
-      @id = objectsRegistry.add process_id, routing_id, value
+      @storeId = objectsRegistry.add process_id, routing_id, value
+      @id = value.id
 
       @members = []
       @members.push { name: prop, type: typeof field } for prop, field of value
@@ -67,12 +68,12 @@ ipc.on 'ATOM_INTERNAL_MEMBER_GET', (event, process_id, routing_id, id, name) ->
   catch e
     event.result = type: 'error', value: e.message
 
-ipc.on 'ATOM_INTERNAL_GET_OBJECT', (event, process_id, routing_id, id) ->
+ipc.on 'ATOM_INTERNAL_REFERENCE', (event, process_id, routing_id, id) ->
   try
     obj = objectsRegistry.get id
     event.result = new PlainObject(process_id, routing_id, obj)
   catch e
     event.result = type: 'error', value: e.message
 
-ipc.on 'ATOM_INTERNAL_DESTROY', (process_id, routing_id, id) ->
-  objectsRegistry.remove process_id, routing_id, id
+ipc.on 'ATOM_INTERNAL_DEREFERENCE', (process_id, routing_id, storeId) ->
+  objectsRegistry.remove process_id, routing_id, storeId

renderer/api/lib/remote.coffee

@@ -48,7 +48,7 @@ generateFromPainObject = (plain) ->
       # Track delegate object's life time, and tell the browser to clean up
       # when the object is GCed.
       v8_util.setDestructor ret, ->
-        ipc.sendChannel 'ATOM_INTERNAL_DESTROY', plain.id
+        ipc.sendChannel 'ATOM_INTERNAL_DEREFERENCE', plain.storeId
 
       ret
 
@@ -59,5 +59,5 @@ exports.require = (module) ->
 
 # Get object with specified id.
 exports.getObject = (id) ->
-  plain = ipc.sendChannelSync 'ATOM_INTERNAL_GET_OBJECT', id
+  plain = ipc.sendChannelSync 'ATOM_INTERNAL_REFERENCE', id
   generateFromPainObject plain