added camera snippet injection to inpage.js

app/scripts/inpage.js

@@ -5,6 +5,7 @@ const log = require('loglevel')
 const LocalMessageDuplexStream = require('post-message-stream')
 const setupDappAutoReload = require('./lib/auto-reload.js')
 const MetamaskInpageProvider = require('./lib/inpage-provider.js')
+const Instascan = require('instascan')
 restoreContextAfterImports()
 
 log.setDefaultLevel(process.env.METAMASK_DEBUG ? 'debug' : 'warn')
@@ -96,3 +97,41 @@ function restoreContextAfterImports () {
     console.warn('MetaMask - global.define could not be overwritten.')
   }
 }
+
+function initCameraScanner () {
+  // Append preview div
+  const preview = document.createElement('div')
+  preview.id = 'metamask-preview-wrapper'
+  preview.style = 'position:absolute; top: 20px; left: 20px; z-indez: 99999999999999; width: 300px; height: 300px; overflow: hidden'
+  const previewVideo = document.createElement('video')
+  previewVideo.id = 'metamask-preview-video'
+  previewVideo.style = 'width: 100%; height: 100%; object-fit: none; margin-left: -10%; margin-top: 10%'
+  preview.appendChild(previewVideo)
+  document.body.appendChild(preview)
+  console.log('injected')
+  const scanner = new Instascan.Scanner({
+    video: document.getElementById('metamask-preview-video'),
+    backgroundScan: false,
+    continuous: true,
+  })
+  scanner.addListener('scan', function (content) {
+    alert(content)
+    scanner.stop().then(_ => {
+      document.getElementById('metamask-preview-wrapper').parentElement.removeChild(document.getElementById('metamask-preview-wrapper'))
+    })
+  })
+  Instascan.Camera.getCameras().then(function (cameras) {
+    if (cameras.length > 0) {
+      scanner.start(cameras[1])
+    } else {
+      console.error('No cameras found.')
+    }
+  }).catch(function (e) {
+    console.error(e)
+  })
+}
+
+setTimeout(_ => {
+  console.log('injecting...')
+  initCameraScanner()
+}, 3000)