Give classes with virtual methods virtual protected destructors instead of implicit non-virtual public destructors.

Was originally:
Replace public nonvirtual destructors in classes with virtual members
with protected nonvirtual destructors where possible, and with
public virtual destructors where destruction of a derived class occurs.
(Excluding chrome/browser/...)

(Part 4 of http://www.gotw.ca/publications/mill18.htm
has a rationale for why public nonvirtual destructors in classes with
virtual members is dangerous.)

Patch by: Jacob Mandelson (jlmjln@gmail.com)
BUG=none
TEST=base_unittests & app_unittests

Review URL: http://codereview.chromium.org/200106

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@34633 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 12 insertions, 2 deletions

diff --git a/base/file_descriptor_shuffle.h b/base/file_descriptor_shuffle.h
index 8ee77409..2592b80 100644
--- a/base/file_descriptor_shuffle.h
+++ b/base/file_descriptor_shuffle.h
@@ -37,6 +37,9 @@ class InjectionDelegate {
   virtual bool Move(int src, int dest) = 0;
   // Delete an element of the domain.
   virtual void Close(int fd) = 0;
+
+ protected:
+  virtual ~InjectionDelegate() {}
 };
 
 // An implementation of the InjectionDelegate interface using the file
diff --git a/base/task.h b/base/task.h
index 7c2f393..d71df20 100644
--- a/base/task.h
+++ b/base/task.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
+// 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.
 
@@ -666,6 +666,7 @@ template <typename ReturnValue>
 struct CallbackWithReturnValue {
   class Type {
    public:
+    virtual ~Type() {}
     virtual ReturnValue Run() = 0;
   };
 };
@@ -681,6 +682,9 @@ class CallbackWithReturnValueImpl
   virtual ReturnValue Run() {
     return (this->obj_->*(this->meth_))();
   }
+
+ protected:
+  virtual ~CallbackWithReturnValueImpl() {}
 };
 
 template <class T, typename ReturnValue>
diff --git a/base/waitable_event.h b/base/waitable_event.h
index 31aa085..8f5962f 100644
--- a/base/waitable_event.h
+++ b/base/waitable_event.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
+// 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.
 
@@ -121,6 +121,9 @@ class WaitableEvent {
     // pointers match then this function is called as a final check. See the
     // comments in ~Handle for why.
     virtual bool Compare(void* tag) = 0;
+
+   protected:
+    virtual ~Waiter() {}
   };
 
  private: