[CCA WebUI] Add WebUI implementations for localStorage.

This CL adds implementations for localStorageGet/Set/Remove for the WebUI
version of the Camera App browser proxy.

Bug: 980846
Change-Id: I36194dd685f8c4e9f2d8fd4e001777d547e4b25e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1713549Reviewed-by: Giovanni Ortuño Urquidi <ortuno@chromium.org>
Commit-Queue: calamity <calamity@chromium.org>
Cr-Commit-Position: refs/heads/master@{#680745}

chrome/browser/resources/chromeos/camera/src/js/browser_proxy/browser_proxy_interface.js

@@ -30,7 +30,7 @@ cca.proxy.BrowserProxy = class {
 
   /**
    * @param {(string|!Array<string>|!Object)} keys
-   * @param {function(!Object)=} callback
+   * @param {function(!Object)} callback
    */
   localStorageGet(keys, callback) {}
 

chrome/browser/resources/chromeos/camera/src/js/browser_proxy/webui_browser_proxy.js

@@ -39,17 +39,50 @@ class WebUIBrowserProxy {
 
   /** @override */
   localStorageGet(keys, callback) {
-    NOTIMPLEMENTED();
+    let sanitizedKeys = [];
+    if (typeof keys === 'string') {
+      sanitizedKeys = [keys];
+    } else if (Array.isArray(keys)) {
+      sanitizedKeys = keys;
+    } else if (keys !== null && typeof keys === 'object') {
+      sanitizedKeys = Object.keys(keys);
+    } else {
+      throw new Error('WebUI localStorageGet() cannot be run with ' + keys);
+    }
+
+    let result = {};
+    for (let key of sanitizedKeys) {
+      let value = window.localStorage.getItem(key);
+      if (value !== null) {
+        value = JSON.parse(value);
+      }
+      result[key] = value === null ? {} : value;
+    }
+
+    callback(result);
   }
 
   /** @override */
   localStorageSet(items, callback) {
-    NOTIMPLEMENTED();
+    for (let [key, val] of Object.entries(items)) {
+      window.localStorage.setItem(key, JSON.stringify(val));
+    }
+    if (callback) {
+      callback();
+    }
   }
 
   /** @override */
   localStorageRemove(items, callback) {
-    NOTIMPLEMENTED();
+    if (typeof items === 'string') {
+      items = [items];
+    }
+    for (let key of items) {
+      window.localStorage.removeItem(key);
+    }
+    if (callback) {
+      callback();
+    }
   }
 }