[Passwords/Settings] Avoid duplicated checks in PasswordsSection

It seems over time, different features added to passwords settings
ended up implementing the check of whether there are saved passwords
resulting in hasSome_, hasStoredPasswords_ and hasPasswords_ (e.g.
crrev.com/c/1047867, crrev.com/2107524). This CL summarizes these in
a single hasSavedPasswords_ property, reflecting the name of the
corresponding array. The same is done for the array of exceptions.

The motivations here are: a) Keep simplifying the PasswordsSection code;
b) Avoid the use of hasStoredPasswords_ in setSavedPasswordsListener,
allowing to extract that code into a new behavior in the next CL.

Bug: None
Change-Id: Ib39c29f3cc5fd90bde3313971eb95d17b3ed9fe1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2225905
Commit-Queue: Victor Vianna <victorvianna@google.com>
Reviewed-by: Friedrich [CET] <fhorschig@chromium.org>
Reviewed-by: Jan Wilken Dörrie <jdoerrie@chromium.org>
Cr-Commit-Position: refs/heads/master@{#774589}

chrome/browser/resources/settings/autofill_page/passwords_section.html

@@ -135,7 +135,7 @@
       </h2>
       <template is="dom-if"
           if="[[showImportOrExportPasswords_(
-                    showExportPasswords_, showImportPasswords_)]]">
+                    hasSavedPasswords_, showImportPasswords_)]]">
         <cr-icon-button class="icon-more-vert header-aligned-button"
             id="exportImportMenuButton"
             on-click="onImportExportMenuTap_" title="$i18n{moreActions}"
@@ -151,8 +151,7 @@
       should-show-storage-details="[[shouldShowStorageDetails_]]">
       <div slot="body" class="list-frame">
         <div id="savedPasswordsHeaders" class="list-item column-header"
-            hidden$="[[!hasSome_(savedPasswords, savedPasswords.splices)]]"
-            aria-hidden="true">
+            hidden$="[[!hasSavedPasswords_]]" aria-hidden="true">
           <div class="website-column">$i18n{editPasswordWebsiteLabel}</div>
           <div class="username-column">
             $i18n{editPasswordUsernameLabel}
@@ -180,7 +179,7 @@
           </template>
         </iron-list>
         <div id="noPasswordsLabel" class="list-item"
-            hidden$="[[hasSome_(savedPasswords, savedPasswords.splices)]]">
+            hidden$="[[hasSavedPasswords_]]">
           $i18n{noPasswordsFound}
         </div>
       </div>
@@ -191,7 +190,7 @@
         $i18n{import}
       </button>
       <button id="menuExportPassword" class="dropdown-item"
-          on-click="onExportTap_" hidden="[[!showExportPasswords_]]">
+          on-click="onExportTap_" hidden="[[!hasSavedPasswords_]]">
         $i18n{exportMenuItem}
       </button>
     </cr-action-menu>
@@ -229,7 +228,7 @@
         </div>
       </template>
       <div id="noExceptionsLabel" class="list-item"
-          hidden$="[[hasSome_(passwordExceptions)]]">
+          hidden$="[[hasPasswordExceptions_]]">
         $i18n{noExceptionsFound}
       </div>
     </div>

chrome/browser/resources/settings/autofill_page/passwords_section.js

@@ -153,16 +153,23 @@ Polymer({
     },
 
     /** @private */
-    hasStoredPasswords_: {
+    hasSavedPasswords_: {
       type: Boolean,
-      value: false,
+      computed:
+          'computeHasSavedPasswords_(savedPasswords, savedPasswords.splices)',
+    },
+
+    /** @private */
+    hasPasswordExceptions_: {
+      type: Boolean,
+      computed: 'computeHasPasswordExceptions_(passwordExceptions)',
     },
 
     shouldShowBanner_: {
       type: Boolean,
       value: true,
       computed: 'computeShouldShowBanner_(hasLeakedCredentials_,' +
-          'signedIn_, hasNeverCheckedPasswords_, hasStoredPasswords_)',
+          'signedIn_, hasNeverCheckedPasswords_, hasSavedPasswords_)',
     },
 
     /**
@@ -188,12 +195,6 @@ Polymer({
       computed: 'computeHidePasswordsLink_(syncPrefs_, syncStatus_)',
     },
 
-    /** @private */
-    showExportPasswords_: {
-      type: Boolean,
-      computed: 'hasPasswords_(savedPasswords.splices)',
-    },
-
     /** @private */
     showImportPasswords_: {
       type: Boolean,
@@ -460,12 +461,28 @@ Polymer({
         (!!this.syncStatus_ && !this.syncStatus_.signedIn) && this.signedIn_;
   },
 
+  /**
+   * @return {boolean}
+   * @private
+   */
+  computeHasSavedPasswords_() {
+    return this.savedPasswords.length > 0;
+  },
+
+  /**
+   * @return {boolean}
+   * @private
+   */
+  computeHasPasswordExceptions_() {
+    return this.passwordExceptions.length > 0;
+  },
+
   /**
    * @return {boolean}
    * @private
    */
   computeShouldShowBanner_() {
-    return this.signedIn_ && this.hasStoredPasswords_ &&
+    return this.signedIn_ && this.hasSavedPasswords_ &&
         this.hasNeverCheckedPasswords_ && !this.hasLeakedCredentials_;
   },
 
@@ -587,29 +604,12 @@ Polymer({
     this.passwordManager_.optInForAccountStorage(false);
   },
 
-  /**
-   * Returns true if the list exists and is not empty.
-   * @param {Array<Object>} list
-   * @return {boolean}
-   * @private
-   */
-  hasSome_(list) {
-    return !!(list && list.length);
-  },
-
-  /** @private */
-  hasPasswords_() {
-    return this.savedPasswords.length > 0;
-  },
-
   /**
    * @private
-   * @param {boolean} showExportPasswords
-   * @param {boolean} showImportPasswords
    * @return {boolean}
    */
-  showImportOrExportPasswords_(showExportPasswords, showImportPasswords) {
-    return showExportPasswords || showImportPasswords;
+  showImportOrExportPasswords_() {
+    return this.hasSavedPasswords_ || this.showImportPasswords_;
   },
 
   /**