Make download items drag sources on OS X.

chrome/browser/cocoa/draggable_button_unittest.mm

+// Copyright (c) 2010 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 "base/scoped_nsobject.h"
+#import "chrome/browser/cocoa/bookmark_button.h"
+#import "chrome/browser/cocoa/cocoa_test_helper.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "testing/platform_test.h"
+
+NSEvent* Event(const NSPoint point, const NSEventType type) {
+  static NSUInteger eventNumber = 0;  // thx shess
+  return [NSEvent mouseEventWithType:type
+                            location:point
+                       modifierFlags:0
+                           timestamp:0
+                        windowNumber:183  // picked out of thin air.
+                             context:nil
+                         eventNumber:eventNumber++
+                          clickCount:1
+                            pressure:0.0];
+}
+
+// Make sure the basic case of "click" still works.
+TEST(DraggableButtonTest, DownUp) {
+  scoped_nsobject<NSMutableArray> array;
+  array.reset([[NSMutableArray alloc] init]);
+  [array addObject:@"foo"];
+  [array addObject:@"bar"];
+
+  scoped_nsobject<DraggableButton> button;
+  button.reset([[DraggableButton alloc] initWithFrame:NSMakeRect(0,0,500,500)]);
+
+  [button setTarget:array.get()];
+  [button setAction:@selector(removeAllObjects)];
+  EXPECT_FALSE([[button cell] isHighlighted]);
+
+  NSEvent* downEvent(Event(NSMakePoint(10,10), NSLeftMouseDown));
+  NSEvent* upEvent(Event(NSMakePoint(10,10), NSLeftMouseDown));
+  [button mouseDown:downEvent];
+  EXPECT_TRUE([[button cell] isHighlighted]);
+  [button mouseUp:upEvent];
+  EXPECT_FALSE([[button cell] isHighlighted]);
+  EXPECT_FALSE([array count]);  // confirms target/action fired
+}