cocoa: fix a11y labeling & state on search icon

chrome/browser/ui/cocoa/location_bar/location_bar_decoration.mm

Index: chrome/browser/ui/cocoa/location_bar/location_bar_decoration.mm
diff --git a/chrome/browser/ui/cocoa/location_bar/location_bar_decoration.mm b/chrome/browser/ui/cocoa/location_bar/location_bar_decoration.mm
index d9c784882e4c572ef57e3de8187a0c1566efa75d..7182d5e41d7ccd409ff4e17e147ede8fbe025601 100644
--- a/chrome/browser/ui/cocoa/location_bar/location_bar_decoration.mm
+++ b/chrome/browser/ui/cocoa/location_bar/location_bar_decoration.mm
@@ -88,7 +88,8 @@ - (void)actionDidHappen {
 }
 
 - (NSString*)accessibilityLabel {
-  return owner_->GetToolTip();
+  NSString* label = owner_->GetAccessibilityLabel();
+  return label ? label : owner_->GetToolTip();
 }
 
 @end
@@ -162,6 +163,10 @@ - (void)mouseExited:(NSEvent*)event {
   return NSInsetRect(frame, 0.0, kBackgroundFrameYInset);
 }
 
+void LocationBarDecoration::UpdateAccessibilityView() {
+  [accessibility_view_.get() setEnabled:AcceptsMousePress()];
+}
+
 void LocationBarDecoration::DrawInFrame(NSRect frame, NSView* control_view) {
   NOTREACHED();
 }
@@ -197,6 +202,10 @@ - (void)mouseExited:(NSEvent*)event {
   return nil;
 }
 
+NSString* LocationBarDecoration::GetAccessibilityLabel() {
+  return nil;
+}
+
 CrTrackingArea* LocationBarDecoration::SetupTrackingArea(NSRect frame,
                                                          NSView* control_view) {
   if (!AcceptsMousePress() || !control_view)