Force NetworkConfig.securityType_ to be an enum, not a string

When we converted network_config.js to use == instead of ===, we broke
some subtle logic when using <network-config-select> with enum values:

The <option> children of the <select> element will always have a string
value, even if the value is set to a number. Thus the data binding will
quietly replace the enums with strings.

Thus was fine when using == (since "2" == 2 in JS) but breaks with ===.

Since securityType_ is the only place where we use network-config-select
with an enum, the simplest fix is to force it to an enum in
updateSecurity_().

If we use network-config-select for any more enums, we should fix it
to do the conversion if the items are numbers and not strings.

Bug: 1046149
Change-Id: Iacdf4f45296483311566ab1b0748d6947ca1429b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2027067Reviewed-by: Jon Mann <jonmann@chromium.org>
Commit-Queue: Steven Bennetts <stevenjb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#736540}

ui/webui/resources/cr_components/chromeos/network/network_config.js

@@ -190,8 +190,9 @@ Polymer({
 
     /**
      * Security value, used for Ethernet and Wifi and to detect when Security
-     * changes.
-     * @private {!chromeos.networkConfig.mojom.SecurityType|undefined}
+     * changes. NOTE: the <select> element might set this to a string, see
+     * crbug.com/1046149.
+     * @private {!chromeos.networkConfig.mojom.SecurityType|string|undefined}
      */
     securityType_: Number,
 
@@ -375,7 +376,8 @@ Polymer({
       // Allow securityType_ to be set externally (e.g. in tests).
       if (mojoType === mojom.NetworkType.kWiFi &&
           this.securityType_ !== undefined) {
-        managedProperties.typeProperties.wifi.security = this.securityType_;
+        managedProperties.typeProperties.wifi.security =
+            /**@type{!mojom.SecurityType}*/ (this.securityType_);
       }
       this.managedProperties_ = managedProperties;
       this.mojoType_ = mojoType;
@@ -832,6 +834,13 @@ Polymer({
       return;
     }
     const type = this.mojoType_;
+    // Force |securityType_| to an enum value when the <select> element sets it
+    // to a string. See crbug.com/1046149 for details.
+    if (typeof (this.securityType_) === 'string') {
+      this.securityType_ =
+          /** @type{!chromeos.networkConfig.mojom.SecurityType}*/ (
+              Number.parseInt(/** @type{string}*/ (this.securityType_), 10));
+    }
     const security = this.securityType_;
     if (type === mojom.NetworkType.kWiFi) {
       this.configProperties_.typeConfig.wifi.security = security;

ui/webui/resources/cr_components/chromeos/network/network_config_select.js

@@ -106,8 +106,9 @@ Polymer({
   },
 
   /**
-   * @param {string|!chromeos.networkConfig.mojom.NetworkCertificate} item
-   * @return {string}
+   * @param {string|number|!chromeos.networkConfig.mojom.NetworkCertificate}
+   *     item
+   * @return {string|number}
    * @private
    */
   getItemValue_(item) {
@@ -116,7 +117,7 @@ Polymer({
                  item)
           .hash;
     }
-    return /** @type {string} */ (item);
+    return /** @type {string|number}*/ (item);
   },
 
   /**