Disable token price polling when no client is active

app/scripts/background.js

@@ -200,6 +200,7 @@ function setupController (initState, initLangCode) {
     if (isMetaMaskInternalProcess) {
       // communication with popup
       popupIsOpen = popupIsOpen || (remotePort.name === 'popup')
+      controller.isClientOpen = true
       controller.setupTrustedCommunication(portStream, 'MetaMask')
       // record popup as closed
       if (remotePort.sender.url.match(/home.html$/)) {
@@ -211,6 +212,8 @@ function setupController (initState, initLangCode) {
           if (remotePort.sender.url.match(/home.html$/)) {
             openMetamaskTabsIDs[remotePort.sender.tab.id] = false
           }
+          controller.isClientOpen = popupIsOpen ||
+            Object.keys(openMetamaskTabsIDs).some(key => openMetamaskTabsIDs[key])
         })
       }
       if (remotePort.name === 'notification') {

app/scripts/controllers/token-rates.js

@@ -23,6 +23,7 @@ class TokenRatesController {
    * Updates exchange rates for all tokens
    */
   async updateExchangeRates () {
+    if (!this.isActive) { return }
     const contractExchangeRates = {}
     for (const i in this._tokens) {
       const address = this._tokens[i].address

app/scripts/metamask-controller.js

@@ -269,6 +269,7 @@ module.exports = class MetamaskController extends EventEmitter {
 
     // memStore -> transform -> publicConfigStore
     this.on('update', (memState) => {
+      this.isClientOpenAndUnlocked = memState.isUnlocked && this._isClientOpen
       const publicState = selectPublicState(memState)
       publicConfigStore.putState(publicState)
     })
@@ -1030,4 +1031,12 @@ module.exports = class MetamaskController extends EventEmitter {
     }
   }
 
+  set isClientOpen (open) {
+    this._isClientOpen = open
+    this.isClientOpenAndUnlocked = this.getState().isUnlocked && open
+  }
+
+  set isClientOpenAndUnlocked (active) {
+    this.tokenRatesController.isActive = active
+  }
 }

test/unit/token-rates-controller.js

@@ -20,6 +20,7 @@ describe('TokenRatesController', () => {
 
   it('should fetch each token rate based on address', async () => {
     const controller = new TokenRatesController()
+    controller.isActive = true
     controller.fetchExchangeRate = address => address
     controller.tokens = [{ address: 'foo' }, { address: 'bar' }]
     await controller.updateExchangeRates()