mac: Add support for asynchronous dictionary lookup

content/browser/renderer_host/render_widget_host_view_mac.mm

Index: content/browser/renderer_host/render_widget_host_view_mac.mm
diff --git a/content/browser/renderer_host/render_widget_host_view_mac.mm b/content/browser/renderer_host/render_widget_host_view_mac.mm
index 510dec1e135d990e89ed2b10e04093964c7e7f18..13d4345b2de4721daa8a484a7d377ccbf4c9251a 100644
--- a/content/browser/renderer_host/render_widget_host_view_mac.mm
+++ b/content/browser/renderer_host/render_widget_host_view_mac.mm
@@ -2627,6 +2627,22 @@ void RenderWidgetHostViewMac::TickPendingLatencyInfoDelay() {
   [responderDelegate_ touchesEndedWithEvent:event];
 }
 
+- (void)quickLookWithEvent:(NSEvent*)event {
+  NSPoint point = [self convertPoint:[event locationInWindow] fromView:nil];
+  TextInputClientMac::GetInstance()->GetStringAtPoint(
+      renderWidgetHostView_->render_widget_host_,
+      gfx::Point(point.x, NSHeight([self frame]) - point.y),
+      ^(NSAttributedString* string, NSRect rect){
+          DCHECK([NSThread isMainThread]);
+          if (string) {
+            NSPoint stringPoint = rect.origin;
+            stringPoint.y = NSHeight([self frame]) - NSMaxY(rect);
+            [self showDefinitionForAttributedString:string atPoint:stringPoint];
+          }
+      }
+  );
+}
+
 // This method handles 2 different types of hardware events.
 // (Apple does not distinguish between them).
 //  a. Scrolling the middle wheel of a mouse.