mac: Add support for asynchronous dictionary lookup

content/browser/renderer_host/render_widget_host_view_mac.mm

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/renderer_host/render_widget_host_view_mac.h"
 
 #import <objc/runtime.h>
 #include <QuartzCore/QuartzCore.h>
 
 #include "base/basictypes.h"
@@ skipping 2777 matching lines @@
 - (void)touchesBeganWithEvent:(NSEvent*)event {
   [responderDelegate_ touchesBeganWithEvent:event];
 }
 - (void)touchesCancelledWithEvent:(NSEvent*)event {
   [responderDelegate_ touchesCancelledWithEvent:event];
 }
 - (void)touchesEndedWithEvent:(NSEvent*)event {
   [responderDelegate_ touchesEndedWithEvent:event];
 }
 
+// This is invoked only on 10.8 or newer when the user taps a word using
+// three fingers.
+- (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, NSPoint baselinePoint) {
+          if (string && [string length] > 0) {
+            dispatch_async(dispatch_get_main_queue(), ^{
+                [self showDefinitionForAttributedString:string
+                                                atPoint:baselinePoint];
+            });
+          }
+      }
+  );
+}
+
 // This method handles 2 different types of hardware events.
 // (Apple does not distinguish between them).
 //  a. Scrolling the middle wheel of a mouse.
 //  b. Swiping on the track pad.
 //
 // This method is responsible for 2 types of behavior:
 //  a. Scrolling the content of window.
 //  b. Navigating forwards/backwards in history.
 //
 // This is a brief description of the logic:
@@ skipping 1466 matching lines @@
                                    CGColorGetConstantColor(kCGColorWhite));
     CGContextFillRect(context, clipRect);
   }
 }
 
 - (void)disableRendering {
   renderWidgetHostView_ = NULL;
 }
 
 @end  // implementation SoftwareLayer