--- a/browser/extensions/formautofill/FormAutofillHandler.jsm
+++ b/browser/extensions/formautofill/FormAutofillHandler.jsm
@@ -133,17 +133,17 @@ class FormAutofillSection {
 
   get allFieldNames() {
     if (!this._cacheValue.allFieldNames) {
       this._cacheValue.allFieldNames = this._validDetails.map(record => record.fieldName);
     }
     return this._cacheValue.allFieldNames;
   }
 
-  getFieldDetailByName(fieldName) {
+  _getFieldDetailByName(fieldName) {
     return this._validDetails.find(detail => detail.fieldName == fieldName);
   }
 
   _getTargetSet() {
     let fieldDetail = this._focusedDetail;
     if (!fieldDetail) {
       return null;
     }
@@ -176,26 +176,26 @@ class FormAutofillSection {
     return this._cacheValue.oneLineStreetAddress[address];
   }
 
   _addressTransformer(profile) {
     if (profile["street-address"]) {
       // "-moz-street-address-one-line" is used by the labels in
       // ProfileAutoCompleteResult.
       profile["-moz-street-address-one-line"] = this._getOneLineStreetAddress(profile["street-address"]);
-      let streetAddressDetail = this.getFieldDetailByName("street-address");
+      let streetAddressDetail = this._getFieldDetailByName("street-address");
       if (streetAddressDetail &&
           (streetAddressDetail.elementWeakRef.get() instanceof Ci.nsIDOMHTMLInputElement)) {
         profile["street-address"] = profile["-moz-street-address-one-line"];
       }
 
       let waitForConcat = [];
       for (let f of ["address-line3", "address-line2", "address-line1"]) {
         waitForConcat.unshift(profile[f]);
-        if (this.getFieldDetailByName(f)) {
+        if (this._getFieldDetailByName(f)) {
           if (waitForConcat.length > 1) {
             profile[f] = FormAutofillUtils.toOneLineAddress(waitForConcat);
           }
           waitForConcat = [];
         }
       }
     }
   }
@@ -206,17 +206,17 @@ class FormAutofillSection {
    * @param {Object} profile
    *        A profile to be converted.
    */
   _telTransformer(profile) {
     if (!profile.tel || !profile["tel-national"]) {
       return;
     }
 
-    let detail = this.getFieldDetailByName("tel");
+    let detail = this._getFieldDetailByName("tel");
     if (!detail) {
       return;
     }
 
     let element = detail.elementWeakRef.get();
     let _pattern;
     let testPattern = str => {
       if (!_pattern) {
@@ -255,17 +255,17 @@ class FormAutofillSection {
   }
 
   _matchSelectOptions(profile) {
     if (!this._cacheValue.matchingSelectOption) {
       this._cacheValue.matchingSelectOption = new WeakMap();
     }
 
     for (let fieldName in profile) {
-      let fieldDetail = this.getFieldDetailByName(fieldName);
+      let fieldDetail = this._getFieldDetailByName(fieldName);
       if (!fieldDetail) {
         continue;
       }
 
       let element = fieldDetail.elementWeakRef.get();
       if (ChromeUtils.getClassName(element) !== "HTMLSelectElement") {
         continue;
       }
@@ -292,17 +292,17 @@ class FormAutofillSection {
     }
   }
 
   _creditCardExpDateTransformer(profile) {
     if (!profile["cc-exp"]) {
       return;
     }
 
-    let detail = this.getFieldDetailByName("cc-exp");
+    let detail = this._getFieldDetailByName("cc-exp");
     if (!detail) {
       return;
     }
 
     let element = detail.elementWeakRef.get();
     if (element.tagName != "INPUT" || !element.placeholder) {
       return;
     }
@@ -325,17 +325,17 @@ class FormAutofillSection {
       profile["cc-exp"] = String(ccExpYear).substr(-1 * result[1].length) +
                           result[2] +
                           String(ccExpMonth).padStart(result[3].length, "0");
     }
   }
 
   _adaptFieldMaxLength(profile) {
     for (let key in profile) {
-      let detail = this.getFieldDetailByName(key);
+      let detail = this._getFieldDetailByName(key);
       if (!detail) {
         continue;
       }
 
       let element = detail.elementWeakRef.get();
       if (!element) {
         continue;
       }
@@ -415,33 +415,33 @@ class FormAutofillSection {
         // For the focused input element, it will be filled with a valid value
         // anyway.
         // For the others, the fields should be only filled when their values
         // are empty.
         let focusedInput = focusedDetail.elementWeakRef.get();
         if (element == focusedInput ||
             (element != focusedInput && !element.value)) {
           element.setUserInput(value);
-          this.changeFieldState(fieldDetail, FIELD_STATES.AUTO_FILLED);
+          this._changeFieldState(fieldDetail, FIELD_STATES.AUTO_FILLED);
         }
       } else if (ChromeUtils.getClassName(element) === "HTMLSelectElement") {
         let cache = this._cacheValue.matchingSelectOption.get(element) || {};
         let option = cache[value] && cache[value].get();
         if (!option) {
           continue;
         }
         // Do not change value or dispatch events if the option is already selected.
         // Use case for multiple select is not considered here.
         if (!option.selected) {
           option.selected = true;
           element.dispatchEvent(new element.ownerGlobal.UIEvent("input", {bubbles: true}));
           element.dispatchEvent(new element.ownerGlobal.Event("change", {bubbles: true}));
         }
         // Autofill highlight appears regardless if value is changed or not
-        this.changeFieldState(fieldDetail, FIELD_STATES.AUTO_FILLED);
+        this._changeFieldState(fieldDetail, FIELD_STATES.AUTO_FILLED);
       }
       if (fieldDetail.state == FIELD_STATES.AUTO_FILLED) {
         element.addEventListener("input", this, {mozSystemGroup: true});
       }
     }
   }
 
   /**
@@ -481,17 +481,17 @@ class FormAutofillSection {
             value = "";
           }
         }
       } else if (element.value) {
         // Skip the field if it already has text entered.
         continue;
       }
       element.previewValue = value;
-      this.changeFieldState(fieldDetail, value ? FIELD_STATES.PREVIEW : FIELD_STATES.NORMAL);
+      this._changeFieldState(fieldDetail, value ? FIELD_STATES.PREVIEW : FIELD_STATES.NORMAL);
     }
   }
 
   /**
    * Clear preview text and background highlight of all fields.
    */
   clearPreviewedFormFields() {
     log.debug("clear previewed fields in:", this.form);
@@ -507,17 +507,17 @@ class FormAutofillSection {
       element.previewValue = "";
 
       // We keep the state if this field has
       // already been auto-filled.
       if (fieldDetail.state == FIELD_STATES.AUTO_FILLED) {
         continue;
       }
 
-      this.changeFieldState(fieldDetail, FIELD_STATES.NORMAL);
+      this._changeFieldState(fieldDetail, FIELD_STATES.NORMAL);
     }
   }
 
   /**
    * Clear value and highlight style of all filled fields.
    */
   clearPopulatedForm() {
     let fieldDetails = this._getFieldDetails();
@@ -540,17 +540,17 @@ class FormAutofillSection {
   /**
    * Change the state of a field to correspond with different presentations.
    *
    * @param {Object} fieldDetail
    *        A fieldDetail of which its element is about to update the state.
    * @param {string} nextState
    *        Used to determine the next state
    */
-  changeFieldState(fieldDetail, nextState) {
+  _changeFieldState(fieldDetail, nextState) {
     let element = fieldDetail.elementWeakRef.get();
 
     if (!element) {
       log.warn(fieldDetail.fieldName, "is unreachable while changing state");
       return;
     }
     if (!(nextState in this._FIELD_STATE_ENUM)) {
       log.warn(fieldDetail.fieldName, "is trying to change to an invalid state");
@@ -573,17 +573,17 @@ class FormAutofillSection {
 
     fieldDetail.state = nextState;
   }
 
   resetFieldStates() {
     for (let fieldDetail of this._validDetails) {
       const element = fieldDetail.elementWeakRef.get();
       element.removeEventListener("input", this, {mozSystemGroup: true});
-      this.changeFieldState(fieldDetail, FIELD_STATES.NORMAL);
+      this._changeFieldState(fieldDetail, FIELD_STATES.NORMAL);
     }
     this.address.filledRecordGUID = null;
     this.creditCard.filledRecordGUID = null;
   }
 
   isFilled() {
     return !!(this.address.filledRecordGUID || this.creditCard.filledRecordGUID);
   }
@@ -704,17 +704,17 @@ class FormAutofillSection {
 
   _normalizeAddress(address) {
     if (!address) {
       return;
     }
 
     // Normalize Country
     if (address.record.country) {
-      let detail = this.getFieldDetailByName("country");
+      let detail = this._getFieldDetailByName("country");
       // Try identifying country field aggressively if it doesn't come from
       // @autocomplete.
       if (detail._reason != "autocomplete") {
         let countryCode = FormAutofillUtils.identifyCountryCode(address.record.country);
         if (countryCode) {
           address.record.country = countryCode;
         }
       }
@@ -760,17 +760,17 @@ class FormAutofillSection {
     switch (event.type) {
       case "input": {
         if (!event.isTrusted) {
           return;
         }
         const target = event.target;
         const fieldDetail = this.getFieldDetailByElement(target);
         const targetSet = this._getTargetSet(target);
-        this.changeFieldState(fieldDetail, FIELD_STATES.NORMAL);
+        this._changeFieldState(fieldDetail, FIELD_STATES.NORMAL);
 
         if (!targetSet.fieldDetails.some(detail => detail.state == FIELD_STATES.AUTO_FILLED)) {
           targetSet.filledRecordGUID = null;
         }
         target.removeEventListener("input", this, {mozSystemGroup: true});
         break;
       }
     }
@@ -918,42 +918,42 @@ class FormAutofillHandler {
       }
       input.addEventListener("input", this, {mozSystemGroup: true});
     }
 
     this.fieldDetails = allValidDetails;
     return allValidDetails;
   }
 
-  hasFilledSection() {
+  _hasFilledSection() {
     return this.sections.some(section => section.isFilled());
   }
 
   /**
    * Processes form fields that can be autofilled, and populates them with the
    * profile provided by backend.
    *
    * @param {Object} profile
    *        A profile to be filled in.
    */
   async autofillFormFields(profile) {
-    let noFilledSectionsPreviously = !this.hasFilledSection();
+    let noFilledSectionsPreviously = !this._hasFilledSection();
     await this.activeSection.autofillFields(profile);
 
     const onChangeHandler = e => {
       if (!e.isTrusted) {
         return;
       }
       if (e.type == "reset") {
         for (let section of this.sections) {
           section.resetFieldStates();
         }
       }
       // Unregister listeners once no field is in AUTO_FILLED state.
-      if (!this.hasFilledSection()) {
+      if (!this._hasFilledSection()) {
         this.form.rootElement.removeEventListener("input", onChangeHandler, {mozSystemGroup: true});
         this.form.rootElement.removeEventListener("reset", onChangeHandler, {mozSystemGroup: true});
       }
     };
 
     if (noFilledSectionsPreviously) {
       // Handle the highlight style resetting caused by user's correction afterward.
       log.debug("register change handler for filled form:", this.form);