Change other usages of .size() to .empty() when applicable.

chrome/browser/ui/cocoa/task_manager_mac.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 "chrome/browser/ui/cocoa/task_manager_mac.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "base/mac/mac_util.h"
@@ skipping 143 matching lines @@
        i = [viewSelection indexLessThanIndex:i]) {
     modelSelection.push_back(viewToModelMap_[i]);
   }
 
   // Sort.
   [self sortShuffleArray];
 
   // Use the model indices to get the new view indices of the selection, and
   // set selection to that. This assumes that no rows were added or removed
   // (in that case, the selection is cleared before -reloadData is called).
-  if (modelSelection.size() > 0)
+  if (!modelSelection.empty())
     DCHECK_EQ([tableView_ numberOfRows], model_->ResourceCount());
   NSMutableIndexSet* indexSet = [NSMutableIndexSet indexSet];
   for (size_t i = 0; i < modelSelection.size(); ++i)
     [indexSet addIndex:modelToViewMap_[modelSelection[i]]];
   [tableView_ selectRowIndexes:indexSet byExtendingSelection:NO];
 
   [tableView_ reloadData];
   [self adjustSelectionAndEndProcessButton];
 }
 
@@ skipping 451 matching lines @@
       // "Task Manager" so close the existing window and fall through to
       // open a new one.
       [[instance_->window_controller_ window] close];
     }
   }
   // Create a new instance.
   instance_ = new TaskManagerMac(TaskManager::GetInstance(),
                                  highlight_background_resources);
   instance_->model_->StartUpdating();
 }