[Mac] Make CocoaTest::TearDown() more scalable in the face of valgrind.

chrome/browser/cocoa/cocoa_test_helper.h

 // Copyright (c) 2009 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.
 
 #ifndef CHROME_BROWSER_COCOA_COCOA_TEST_HELPER_H_
 #define CHROME_BROWSER_COCOA_COCOA_TEST_HELPER_H_
 
 #import <Cocoa/Cocoa.h>
 #include <vector>
 
@@ skipping 63 matching lines @@
   // then close them in TearDown before calling CocoaTest::TearDown.
   virtual void TearDown();
 
   // Retuns a test window that can be used by views and other UI objects
   // as part of their tests. Is created lazily, and will be closed correctly
   // in CocoaTest::TearDown. Note that it is a CocoaTestHelperWindow which
   // has special handling for being Key.
   CocoaTestHelperWindow* test_window();
 
  private:
-  // Return a vector of currently open windows. Note that it is a vector
-  // instead of an NSArray because we don't want any retains placed on the
-  // windows in it and that the windows in this list may no longer be valid
-  // NSWindows any time after this returns. You can only use the pointer values
-  // in the vector for comparison purposes.
-  static std::vector<NSWindow*> ApplicationWindows();
+  // Return a set of currently open windows. Avoiding NSArray so
+  // contents aren't retained, the pointer values can only be used for
+  // comparison purposes.  Using std::set to make progress-checking
+  // convenient.
+  static std::set<NSWindow*> ApplicationWindows();
+
+  // Return a set of windows which are in |ApplicationWindows()| but
+  // not |initial_windows_|.
+  std::set<NSWindow*> WindowsLeft();
 
   bool called_tear_down_;
   base::ScopedNSAutoreleasePool pool_;
-  std::vector<NSWindow*> initial_windows_;
+
+  // Windows which existed at the beginning of the test.
+  std::set<NSWindow*> initial_windows_;
+
   // Strong. Lazily created. This isn't wrapped in a scoped_nsobject because
   // we want to call [close] to destroy it rather than calling [release]. We
   // want to verify that [close] is actually removing our window and that it's
   // not hanging around because releaseWhenClosed was set to "no" on the window.
   // It isn't wrapped in a different wrapper class to close it because we
   // need to close it at a very specific time; just before we enter our clean
   // up loop in TearDown.
   CocoaTestHelperWindow* test_window_;
 };
 
@@ skipping 72 matching lines @@
   void clearFirstResponder() {
     [window_ setPretendIsKeyWindow:NO];
     [window_ makeFirstResponder:nil];
   }
 
  private:
   scoped_nsobject<CocoaTestHelperWindow> window_;
 };
 
 #endif  // CHROME_BROWSER_COCOA_COCOA_TEST_HELPER_H_