[Switch Access] Add metrics for errors and unexpected states

Bug: 1018327
Change-Id: I667be3f714fcea00d2238e3f60144d8118c99bbb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1884822Reviewed-by: David Tseng <dtseng@chromium.org>
Commit-Queue: Anastasia Helfinstein <anastasi@google.com>
Cr-Commit-Position: refs/heads/master@{#711812}

chrome/browser/resources/chromeos/switch_access/BUILD.gn

@@ -388,6 +388,7 @@ js_library("switch_access") {
   externs_list = [
     "$externs_path/automation.js",
     "$externs_path/command_line_private.js",
+    "$externs_path/metrics_private.js",
   ]
 }
 

chrome/browser/resources/chromeos/switch_access/focus_ring_manager.js

@@ -69,9 +69,10 @@ class FocusRingManager {
    */
   setColor(color) {
     if (this.colorPattern_.test(color) !== true) {
-      const errorString = 'Problem setting focus ring color: color is not' +
-          'a valid CSS color string.';
-      throw new Error(errorString);
+      throw SwitchAccess.error(
+          SAConstants.ErrorType.INVALID_COLOR,
+          'Problem setting focus ring color: color is not' +
+              'a valid CSS color string.');
     }
     this.rings_.forEach((ring) => ring.color = color);
   }

chrome/browser/resources/chromeos/switch_access/manifest.json.jinja2

@@ -40,6 +40,7 @@
     "clipboard",
     "clipboardRead",
     "commandLinePrivate",
+    "metricsPrivate",
     "settingsPrivate",
     "tabs"
   ],

chrome/browser/resources/chromeos/switch_access/menu_panel.js

@@ -261,14 +261,18 @@ class Panel {
     const elements = document.querySelectorAll('.i18n');
     for (const element of elements) {
       const messageId = element.getAttribute('msgid');
-      if (!messageId)
-        throw new Error('Element has no msgid attribute: ' + element);
+      if (!messageId) {
+        throw SwitchAccess.error(
+            SAConstants.ErrorType.UNTRANSLATED_STRING,
+            'Element has no msgid attribute: ' + element);
+      }
       const translatedMessage =
           chrome.i18n.getMessage('switch_access_' + messageId);
-      if (element.tagName == 'INPUT')
+      if (element.tagName == 'INPUT') {
         element.setAttribute('placeholder', translatedMessage);
-      else
+      } else {
         element.textContent = translatedMessage;
+      }
       element.classList.add('i18n-processed');
     }
   }

chrome/browser/resources/chromeos/switch_access/nodes/node_wrapper.js

@@ -201,7 +201,9 @@ class RootNodeWrapper extends SARootNode {
     const interestingChildren = RootNodeWrapper.getInterestingChildren(root);
 
     if (interestingChildren.length < 1) {
-      throw new Error('Root node must have at least 1 interesting child.');
+      throw SwitchAccess.error(
+          SAConstants.ErrorType.NO_CHILDREN,
+          'Root node must have at least 1 interesting child.');
     }
     let children = interestingChildren.map(childConstructor);
 
@@ -221,7 +223,9 @@ class RootNodeWrapper extends SARootNode {
     const interestingChildren = RootNodeWrapper.getInterestingChildren(root);
 
     if (interestingChildren.length < 1) {
-      throw new Error('Desktop node must have at least 1 interesting child.');
+      throw SwitchAccess.error(
+          SAConstants.ErrorType.MALFORMED_DESKTOP,
+          'Desktop node must have at least 1 interesting child.');
     }
 
     const childConstructor = (autoNode) => new NodeWrapper(autoNode, root);

chrome/browser/resources/chromeos/switch_access/nodes/switch_access_node.js

@@ -114,7 +114,8 @@ class SAChildNode {
    */
   get next() {
     if (!this.next_) {
-      throw new Error(
+      throw SwitchAccess.error(
+          SAConstants.ErrorType.NEXT_UNDEFINED,
           'Next node must be set on all SAChildNodes before navigating');
     }
     return this.next_;
@@ -126,7 +127,8 @@ class SAChildNode {
    */
   get previous() {
     if (!this.previous_) {
-      throw new Error(
+      throw SwitchAccess.error(
+          SAConstants.ErrorType.PREVIOUS_UNDEFINED,
           'Previous node must be set on all SAChildNodes before navigating');
     }
     return this.previous_;
@@ -200,7 +202,10 @@ class SARootNode {
 
     let result = true;
     for (let i = 0; i < this.children_.length; i++) {
-      if (!this.children_[i]) throw new Error('Child cannot be null.');
+      if (!this.children_[i]) {
+        throw SwitchAccess.error(
+            SAConstants.ErrorType.NULL_CHILD, 'Child cannot be null.');
+      }
       result = result && this.children_[i].equals(other.children_[i]);
     }
 
@@ -217,7 +222,9 @@ class SARootNode {
     if (this.children_.length > 0) {
       return this.children_[0];
     } else {
-      throw new Error('Root nodes must contain children.');
+      throw SwitchAccess.error(
+          SAConstants.ErrorType.NO_CHILDREN,
+          'Root nodes must contain children.');
     }
   }
 
@@ -226,7 +233,9 @@ class SARootNode {
     if (this.children_.length > 0) {
       return this.children_[this.children_.length - 1];
     } else {
-      throw new Error('Root nodes must contain children.');
+      throw SwitchAccess.error(
+          SAConstants.ErrorType.NO_CHILDREN,
+          'Root nodes must contain children.');
     }
   }
 
@@ -287,7 +296,9 @@ class SARootNode {
    */
   static connectChildren(children) {
     if (children.length < 1) {
-      throw new Error('Root node must have at least 1 interesting child.');
+      throw SwitchAccess.error(
+          SAConstants.ErrorType.NO_CHILDREN,
+          'Root node must have at least 1 interesting child.');
     }
 
     let previous = children[children.length - 1];

chrome/browser/resources/chromeos/switch_access/preferences.js

@@ -99,7 +99,7 @@ class SwitchAccessPreferences {
   }
 
   /**
-   * Get the boolean value for the given name. Will throw a type error if the
+   * Get the boolean value for the given name. Will throw an error if the
    * value associated with |name| is not a boolean, or is undefined.
    *
    * @param  {SAConstants.Preference} name
@@ -107,10 +107,13 @@ class SwitchAccessPreferences {
    */
   getBooleanPreference(name) {
     const pref = this.preferences_.get(name);
-    if (pref && pref.type === chrome.settingsPrivate.PrefType.BOOLEAN)
+    if (pref && pref.type === chrome.settingsPrivate.PrefType.BOOLEAN) {
       return /** @type {boolean} */ (pref.value);
-    else
-      throw new TypeError('No value of boolean type named \'' + name + '\'');
+    } else {
+      throw SwitchAccess.error(
+          SAConstants.ErrorType.PREFERENCE_TYPE,
+          'No value of boolean type named \'' + name + '\'');
+    }
   }
 
   /**
@@ -122,10 +125,13 @@ class SwitchAccessPreferences {
    */
   getStringPreference(name) {
     const pref = this.preferences_.get(name);
-    if (pref && pref.type === chrome.settingsPrivate.PrefType.STRING)
+    if (pref && pref.type === chrome.settingsPrivate.PrefType.STRING) {
       return /** @type {string} */ (pref.value);
-    else
-      throw new TypeError('No value of string type named \'' + name + '\'');
+    } else {
+      throw SwitchAccess.error(
+          SAConstants.ErrorType.PREFERENCE_TYPE,
+          'No value of string type named \'' + name + '\'');
+    }
   }
 
   /**
@@ -137,8 +143,11 @@ class SwitchAccessPreferences {
    */
   getNumberPreference(name) {
     const value = this.getNumberPreferenceIfDefined(name);
-    if (!value)
-      throw new TypeError('No value of number type named \'' + name + '\'');
+    if (!value) {
+      throw SwitchAccess.error(
+          SAConstants.ErrorType.PREFERENCE_TYPE,
+          'No value of number type named \'' + name + '\'');
+    }
     return value;
   }
 

chrome/browser/resources/chromeos/switch_access/switch_access.js

@@ -206,7 +206,7 @@ class SwitchAccess {
   }
 
   /**
-   * Get the boolean value for the given name. Will throw a type error if the
+   * Get the boolean value for the given name. Will throw an error if the
    * value associated with |name| is not a boolean, or undefined.
    *
    * @override
@@ -218,7 +218,7 @@ class SwitchAccess {
   }
 
   /**
-   * Get the string value for the given name. Will throw a type error if the
+   * Get the string value for the given name. Will throw an error if the
    * value associated with |name| is not a string, or is undefined.
    *
    * @override
@@ -230,7 +230,7 @@ class SwitchAccess {
   }
 
   /**
-   * Get the number value for the given name. Will throw a type error if the
+   * Get the number value for the given name. Will throw an error if the
    * value associated with |name| is not a number, or undefined.
    *
    * @override
@@ -301,6 +301,19 @@ class SwitchAccess {
             .node;
   }
 
+  /*
+   * Creates and records the specified error.
+   * @param {SAConstants.ErrorType} errorType
+   * @param {string} errorString
+   * @return {!Error}
+   */
+  static error(errorType, errorString) {
+    chrome.metricsPrivate.recordEnumerationValue(
+        'Accessibility.CrosSwitchAccess.Error', errorType,
+        SAConstants.ErrorTypeCountForUMA);
+    return new Error(errorString);
+  }
+
   /**
    * Prints out the current Switch Access tree for debugging.
    * @param {boolean=} wholeTree whether to print the whole tree, or the current

chrome/browser/resources/chromeos/switch_access/switch_access_constants.js

@@ -171,3 +171,30 @@ SAConstants.MenuAction = {
   // Set the beginning of a text selection.
   SELECT_START: 'selectStart'
 };
+
+/**
+ * The types of error or unexpected state that can be encountered by Switch
+ * Access.
+ * These values are persisted to logs and should not be renumbered or re-used.
+ * See tools/metrics/histograms/enums.xml.
+ * @enum {number}
+ * @const
+ */
+SAConstants.ErrorType = {
+  UNKNOWN: 0,
+  PREFERENCE_TYPE: 1,
+  UNTRANSLATED_STRING: 2,
+  INVALID_COLOR: 3,
+  NEXT_UNDEFINED: 4,
+  PREVIOUS_UNDEFINED: 5,
+  NULL_CHILD: 6,
+  NO_CHILDREN: 7,
+  MALFORMED_DESKTOP: 8,
+};
+
+/**
+ * The number of values available in the enum SAConstants.ErrorType.
+ * @type {number}
+ * @const
+ */
+SAConstants.ErrorTypeCountForUMA = Object.keys(SAConstants.ErrorType).length;

chrome/browser/resources/chromeos/switch_access/switch_access_interface.js

@@ -67,7 +67,7 @@ class SwitchAccessInterface {
   setPreference(name, value) {}
 
   /**
-   * Get the boolean value for the given name. Will throw a type error if the
+   * Get the boolean value for the given name. Will throw an error if the
    * value associated with |name| is not a boolean, or undefined.
    *
    * @param  {SAConstants.Preference} name
@@ -76,7 +76,7 @@ class SwitchAccessInterface {
   getBooleanPreference(name) {}
 
   /**
-   * Get the string value for the given name. Will throw a type error if the
+   * Get the string value for the given name. Will throw an error if the
    * value associated with |name| is not a string, or is undefined.
    *
    * @param {SAConstants.Preference} name
@@ -85,7 +85,7 @@ class SwitchAccessInterface {
   getStringPreference(name) {}
 
   /**
-   * Get the number value for the given name. Will throw a type error if the
+   * Get the number value for the given name. Will throw an error if the
    * value associated with |name| is not a number, or undefined.
    *
    * @param  {SAConstants.Preference} name