[omnibox] Add name to icon for accessibility description

MacOS is capable of generating an accessibility description for the
search icon on the Omnibox, but we currently don't fill it in. This
CL adds a name to it (and there may be a follow-up to tweak the
"image" string that is also getting appended.)

Bug: 862745
Change-Id: I53f7250c848761127a29bdad4e215830c365bb97
Reviewed-on: https://chromium-review.googlesource.com/1138548Reviewed-by: Justin Donnelly <jdonnelly@chromium.org>
Commit-Queue: Kevin Bailey <krb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#576184}

chrome/browser/ui/views/location_bar/location_icon_view.cc

@@ -80,7 +80,8 @@ bool LocationIconView::ShowBubble(const ui::Event& event) {
 
 void LocationIconView::GetAccessibleNodeData(ui::AXNodeData* node_data) {
   if (location_bar_->GetOmniboxView()->IsEditingOrEmpty()) {
-    node_data->role = ax::mojom::Role::kNone;
+    node_data->role = ax::mojom::Role::kImage;
+    node_data->SetName(l10n_util::GetStringUTF8(IDS_ACC_SEARCH_ICON));
     return;
   }
 

components/omnibox_strings.grdp

@@ -83,6 +83,9 @@
   <message name="IDS_ACC_AUTOCOMPLETE_CLIPBOARD" desc="Text for screenreaders describing a URL from a clipboard.">
     <ph name="LOCATION_TITLE">$2<ex>The Chromium Projects</ex></ph> <ph name="SHORT_URL">$1<ex>www.chromium.org</ex> location from clipboard</ph>
   </message>
+  <message name="IDS_ACC_SEARCH_ICON" desc="Text for screenreaders describing a search icon image.">
+    Search icon
+  </message>
   <!-- Supplement accessibility label with item position, e.g. "1 of 3" -->
   <message name="IDS_ACC_AUTOCOMPLETE_N_OF_M" desc="Text for screenreaders describing the current matche's position in the list of suggestions.">
     <ph name="FRIENDLY_MATCH_TEXT">$1<ex>The Chromium Projects http://www.chromium.org bookmark</ex></ph>, <ph name="MATCH_POSITION">$2<ex>2</ex></ph> of <ph name="NUM_MATCHES">$3<ex>3</ex></ph>