Settings: Remove usage of exportPath

- Replace exportPath() with updatePrefPath_() in prefs.js
- Make exportPath() fully private in cr.js and remove parameters that
  are only used from prefs.js.

Bug: 1026426
Change-Id: I58e1da64902ee07ad4298060544056d16cce3413
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2056609Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Commit-Queue: Rebekah Potter <rbpotter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#741701}

chrome/browser/resources/settings/prefs/BUILD.gn

@@ -25,7 +25,6 @@ js_library("prefs") {
     ":pref_util",
     ":prefs_behavior",
     ":prefs_types",
-    "//ui/webui/resources/js:cr",
   ]
   externs_list = [ "$externs_path/settings_private.js" ]
   extra_sources = [ "$interfaces_path/settings_private_interface.js" ]

chrome/browser/resources/settings/prefs/prefs.html

 <link rel="import" href="chrome://resources/html/polymer.html">
 
 <link rel="import" href="chrome://resources/html/assert.html">
-<link rel="import" href="chrome://resources/html/cr.html">
 <link rel="import" href="prefs_types.html">
 
 <script src="prefs.js"></script>

chrome/browser/resources/settings/prefs/prefs.js

@@ -265,6 +265,31 @@ Polymer({
     });
   },
 
+  /**
+   * Builds an object structure for the provided |path| within |prefsObject|,
+   * ensuring that names that already exist are not overwritten. For example:
+   * "a.b.c" -> a = {};a.b={};a.b.c={};
+   * @param {string} path Path to the new pref value.
+   * @param {*} value The value to expose at the end of the path.
+   * @param {Object} prefsObject The prefs object to add the path to.
+   * @private
+   */
+  updatePrefPath_(path, value, prefsObject) {
+    const parts = path.split('.');
+    let cur = prefsObject;
+
+    for (let part; parts.length && (part = parts.shift());) {
+      if (!parts.length) {
+        // last part, set the value.
+        cur[part] = value;
+      } else if (part in cur) {
+        cur = cur[part];
+      } else {
+        cur = cur[part] = {};
+      }
+    }
+  },
+
   /**
    * Updates the prefs model with the given prefs.
    * @param {!Array<!chrome.settingsPrivate.PrefObject>} newPrefs
@@ -280,7 +305,7 @@ Polymer({
 
       if (!deepEqual(this.get(newPrefObj.key, prefs), newPrefObj)) {
         // Add the pref to |prefs|.
-        cr.exportPath(newPrefObj.key, newPrefObj, prefs);
+        this.updatePrefPath_(newPrefObj.key, newPrefObj, prefs);
         // If this.prefs already exists, notify listeners of the change.
         if (prefs == this.prefs) {
           this.notifyPath('prefs.' + newPrefObj.key, newPrefObj);

ui/webui/resources/js/cr.js

@@ -17,22 +17,16 @@ var cr = cr || function(global) {
    * example:
    * "a.b.c" -> a = {};a.b={};a.b.c={};
    * @param {string} name Name of the object that this file defines.
-   * @param {*=} opt_object The object to expose at the end of the path.
-   * @param {Object=} opt_objectToExportTo The object to add the path to;
-   *     default is {@code global}.
    * @return {!Object} The last object exported (i.e. exportPath('cr.ui')
    *     returns a reference to the ui property of window.cr).
    * @private
    */
-  function exportPath(name, opt_object, opt_objectToExportTo) {
+  function exportPath(name) {
     const parts = name.split('.');
-    let cur = opt_objectToExportTo || global;
+    let cur = global;
 
     for (let part; parts.length && (part = parts.shift());) {
-      if (!parts.length && opt_object !== undefined) {
-        // last part and we have an object; use it
-        cur[part] = opt_object;
-      } else if (part in cur) {
+      if (part in cur) {
         cur = cur[part];
       } else {
         cur = cur[part] = {};
@@ -423,7 +417,6 @@ var cr = cr || function(global) {
     defineProperty: defineProperty,
     dispatchPropertyChange: dispatchPropertyChange,
     dispatchSimpleEvent: dispatchSimpleEvent,
-    exportPath: exportPath,
     PropertyKind: PropertyKind,
 
     // C++ <-> JS communication related methods.