SplitSettings: Tooltip and new string for OS search engine selection

* "Preferred search engine"
* "Used by Chrome browser and <device> launcher"

http://screen/zTiXifEKNT6

TODO: Style tooltip to spec. We should change all OS settings tooltips
to use the same styling.

Bug: 978464
Change-Id: If434d82607faaba0278da0a29112e8bd791281d3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1719268Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: James Cook <jamescook@chromium.org>
Cr-Commit-Position: refs/heads/master@{#681070}

chrome/app/os_settings_strings.grdp

@@ -33,7 +33,10 @@
 
   <!-- Search and Assistant section. -->
   <message name="IDS_OS_SETTINGS_SEARCH_ENGINE_LABEL" desc="Label in OS settings describing search engine behavior.">
-    Searches from the app launcher use your browser <ph name="BEGIN_LINK">&lt;a target="_blank" href="$1"&gt;</ph>search engine setting<ph name="END_LINK">&lt;/a&gt;</ph>.
+    Preferred search engine
+  </message>
+  <message name="IDS_OS_SETTINGS_SEARCH_ENGINE_TOOLTIP" desc="Tooltip in OS settings explaining that search engine is used in both the Chrome browser and the Chrome OS app launcher.">
+    Used by Chrome browser and <ph name="DEVICE_TYPE">$1<ex>Chromebook</ex></ph> launcher
   </message>
 
   <!-- Files Page (OS settings) -->

chrome/browser/resources/settings/chromeos/os_search_page/os_search_page.html

@@ -6,6 +6,8 @@
 <link rel="import" href="chrome://resources/cr_elements/shared_vars_css.html">
 <link rel="import" href="chrome://resources/html/assert.html">
 <link rel="import" href="chrome://resources/html/i18n_behavior.html">
+<link rel="import" href="chrome://resources/polymer/v1_0/iron-icon/iron-icon.html">
+<link rel="import" href="chrome://resources/polymer/v1_0/paper-tooltip/paper-tooltip.html">
 <link rel="import" href="../../controls/extension_controlled_indicator.html">
 <link rel="import" href="../../google_assistant_page/google_assistant_page.html">
 <link rel="import" href="../../google_assistant_page/google_assistant_browser_proxy.html">
@@ -27,8 +29,20 @@
         min-height: var(--settings-row-min-height);
       }
 
+      /* TODO(jamescook): Style all OS settings tooltips to new spec. */
+      paper-tooltip {
+        --paper-tooltip: {
+          @apply --cr-tooltip;
+          padding: 12px 10px;
+        };
+      }
+
       iron-icon {
-        padding-inline-end: 16px;
+        --iron-icon-fill-color: var(--google-grey-refresh-500);
+      }
+
+      cr-policy-pref-indicator {
+        padding-inline-end: 8px;
       }
     </style>
     <settings-animated-pages id="pages" section="search"
@@ -40,7 +54,14 @@
         <div class="settings-box first block">
           <div id="search-wrapper">
             <div id="searchExplanation" class="start settings-box-text">
-              $i18nRaw{searchExplanation}
+              $i18n{osSearchEngineLabel}
+              <iron-icon id="help-icon" icon="cr:help-outline"
+                  aria-label="$i18n{osSearchEngineTooltip}"
+                  aria-describedby="tooltip"></iron-icon>
+              <paper-tooltip id="tooltip" for="help-icon" position="bottom"
+                  fit-to-visible-bounds>
+                $i18n{osSearchEngineTooltip}
+              </paper-tooltip>
             </div>
             <template is="dom-if" if="[[isDefaultSearchControlledByPolicy_(
                 prefs.default_search_provider_data.template_url_data)]]">

chrome/browser/ui/webui/settings/settings_localized_strings_provider.cc

@@ -2486,6 +2486,7 @@ void AddSearchStrings(content::WebUIDataSource* html_source, Profile* profile) {
     {"osSearchPageTitle", is_assistant_allowed
                               ? IDS_SETTINGS_SEARCH_AND_ASSISTANT
                               : IDS_SETTINGS_SEARCH},
+    {"osSearchEngineLabel", IDS_OS_SETTINGS_SEARCH_ENGINE_LABEL},
     {"searchGoogleAssistant", IDS_SETTINGS_SEARCH_GOOGLE_ASSISTANT},
     {"searchGoogleAssistantEnabled",
      IDS_SETTINGS_SEARCH_GOOGLE_ASSISTANT_ENABLED},
@@ -2500,6 +2501,9 @@ void AddSearchStrings(content::WebUIDataSource* html_source, Profile* profile) {
       base::ASCIIToUTF16(chrome::kOmniboxLearnMoreURL));
   html_source->AddString("searchExplanation", search_explanation_text);
 #if defined(OS_CHROMEOS)
+  html_source->AddString(
+      "osSearchEngineTooltip",
+      ui::SubstituteChromeOSDeviceType(IDS_OS_SETTINGS_SEARCH_ENGINE_TOOLTIP));
   html_source->AddBoolean("isAssistantAllowed", is_assistant_allowed);
 #endif
 }