Make keyword hint view ("press tab to search foo.com") clickable.

chrome/browser/ui/views/location_bar/location_bar_view.h

Index: chrome/browser/ui/views/location_bar/location_bar_view.h
diff --git a/chrome/browser/ui/views/location_bar/location_bar_view.h b/chrome/browser/ui/views/location_bar/location_bar_view.h
index 0cc4557efe6e6658fa6730600c16cdb9e7aa1db8..b20795ae028b5b7120150476e686cb61cbe9773c 100644
--- a/chrome/browser/ui/views/location_bar/location_bar_view.h
+++ b/chrome/browser/ui/views/location_bar/location_bar_view.h
@@ -27,6 +27,7 @@
 #include "ui/gfx/animation/slide_animation.h"
 #include "ui/gfx/font.h"
 #include "ui/gfx/geometry/rect.h"
+#include "ui/views/controls/button/button.h"
 #include "ui/views/drag_controller.h"
 
 class CommandUpdater;
@@ -67,7 +68,8 @@ class LocationBarView : public LocationBar,
                         public ChromeOmniboxEditController,
                         public DropdownBarHostDelegate,
                         public TemplateURLServiceObserver,
-                        public zoom::ZoomEventManagerObserver {
+                        public zoom::ZoomEventManagerObserver,
+                        public views::ButtonListener {
  public:
   class Delegate {
    public:
@@ -236,6 +238,9 @@ class LocationBarView : public LocationBar,
   // Updates the view for the zoom icon when default zoom levels change.
   void OnDefaultZoomLevelChanged() override;
 
+  // views::ButtonListener:
+  void ButtonPressed(views::Button* sender, const ui::Event& event) override;
+
  private:
   using ContentSettingViews = std::vector<ContentSettingImageView*>;