Fix typo in host_installer.js

BUG=418859

Review URL: https://codereview.chromium.org/615803002

Cr-Commit-Position: refs/heads/master@{#297470}
(cherry picked from commit dbcbacdda074a8281df82fb547c6e2453a61e55b)

[email protected]

Review URL: https://codereview.chromium.org/618173002

Cr-Commit-Position: refs/branch-heads/2171@{#8}
Cr-Branched-From: 267aeeb8d85c8503a7fd12bd14654b8ea78d3974-refs/heads/master@{#297060}
diff --git a/remoting/webapp/host_installer.js b/remoting/webapp/host_installer.js
index 6983a56..48e62a2 100644
--- a/remoting/webapp/host_installer.js
+++ b/remoting/webapp/host_installer.js
@@ -128,7 +128,7 @@
       return Promise.resolve(true);
     }
 
-    if (that.downloadAndWaitForInstallPromise_ !== null) {
+    if (that.downloadAndWaitForInstallPromise_ === null) {
       that.downloadAndWaitForInstallPromise_ = new Promise(
         /** @param {Function} resolve */
         function(resolve){
@@ -160,4 +160,4 @@
     this.checkInstallIntervalId_ = null;
   }
   this.downloadAndWaitForInstallPromise_ = null;
-};
\ No newline at end of file
+};