Add link to Settings page to add accessibility extensions.

See bug for more context; this makes the "Accessibility" section show up
on all platforms, not just Chrome OS, and adds a link to the special
web store page with curated accessibility extensions.

BUG=416983

Review URL: https://codereview.chromium.org/599683002

Cr-Commit-Position: refs/heads/master@{#296561}

chrome/app/chromeos_strings.grdp

@@ -1826,9 +1826,6 @@ Press any key to continue exploring.
   <message name="IDS_OPTIONS_SETTINGS_SECTION_TITLE_LANGUAGE">
     Language
   </message>
-  <message name="IDS_OPTIONS_SETTINGS_SECTION_TITLE_ACCESSIBILITY">
-    Accessibility
-  </message>
   <message name="IDS_OPTIONS_SETTINGS_BATTERY_DESCRIPTION" desc="The 'Battery' button on the chrome://settings page.">
     Battery...
   </message>

chrome/app/generated_resources.grd

@@ -11833,6 +11833,14 @@ Some features may be unavailable.  Please check that the profile exists and you
         System
       </message>
 
+      <!-- Accessibility options -->
+      <message name="IDS_OPTIONS_SETTINGS_SECTION_TITLE_ACCESSIBILITY">
+        Accessibility
+      </message>
+      <message name="IDS_OPTIONS_ACCESSIBILITY_FEATURES_LINK">
+        Add additional accessibility features
+      </message>
+
       <!-- Multiple download warning-->
       <message name="IDS_MULTI_DOWNLOAD_WARNING" desc="Warning invoked if multiple downloads are attempted without user interaction.">
         This site is attempting to download multiple files. Do you want to allow this?

chrome/browser/ui/webui/options/browser_options_handler.cc

@@ -362,6 +362,10 @@ void BrowserOptionsHandler::GetLocalizedValues(base::DictionaryValue* values) {
     { "themes", IDS_THEMES_GROUP_NAME },
 #endif
     { "themesReset", IDS_THEMES_RESET_BUTTON },
+    { "accessibilityTitle",
+      IDS_OPTIONS_SETTINGS_SECTION_TITLE_ACCESSIBILITY },
+    { "accessibilityFeaturesLink",
+      IDS_OPTIONS_ACCESSIBILITY_FEATURES_LINK },
 #if defined(OS_CHROMEOS)
     { "accessibilityExplanation",
       IDS_OPTIONS_SETTINGS_ACCESSIBILITY_EXPLANATION },
@@ -385,8 +389,6 @@ void BrowserOptionsHandler::GetLocalizedValues(base::DictionaryValue* values) {
       IDS_OPTIONS_SETTINGS_ACCESSIBILITY_STICKY_KEYS_DESCRIPTION },
     { "accessibilitySpokenFeedback",
       IDS_OPTIONS_SETTINGS_ACCESSIBILITY_SPOKEN_FEEDBACK_DESCRIPTION },
-    { "accessibilityTitle",
-      IDS_OPTIONS_SETTINGS_SECTION_TITLE_ACCESSIBILITY },
     { "accessibilityVirtualKeyboard",
       IDS_OPTIONS_SETTINGS_ACCESSIBILITY_VIRTUAL_KEYBOARD_DESCRIPTION },
     { "accessibilityAlwaysShowMenu",