MSVC warns when you try to use Base if T has a private destructor,

The common pattern for refcounted types. It does this even though
no attempt to instantiate Base is made.  We disable the warning for
this portion of code.

BUG=none
TEST=try bots.

Review URL: http://codereview.chromium.org/6833006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@81499 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 23 insertions, 0 deletions

diff --git a/base/bind_helpers.h b/base/bind_helpers.h
index 92194e7..3293dbb 100644
--- a/base/bind_helpers.h
+++ b/base/bind_helpers.h
@@ -133,8 +133,17 @@ class SupportsAddRefAndRelease {
     void Release();
   };
 
+// MSVC warns when you try to use Base if T has a private destructor, the
+// common pattern for refcounted types. It does this even though no attempt to
+// instantiate Base is made.  We disable the warning for this definition.
+#if defined(OS_WIN)
+#pragma warning(disable:4624)
+#endif
   struct Base : public T, public BaseMixin {
   };
+#if defined(OS_WIN)
+#pragma warning(default:4624)
+#endif
 
   template <void(BaseMixin::*)(void)>  struct Helper {};
 
diff --git a/base/bind_unittest.cc b/base/bind_unittest.cc
index b3e0160..c131a86 100644
--- a/base/bind_unittest.cc
+++ b/base/bind_unittest.cc
@@ -48,6 +48,11 @@ class HasRef : public NoRef {
   DISALLOW_COPY_AND_ASSIGN(HasRef);
 };
 
+class HasRefPrivateDtor : public HasRef {
+ private:
+  ~HasRefPrivateDtor() {}
+};
+
 static const int kParentValue = 1;
 static const int kChildValue = 2;
 
@@ -425,6 +430,11 @@ TEST_F(BindTest, ArrayArgumentBinding) {
 
 // Verify SupportsAddRefAndRelease correctly introspects the class type for
 // AddRef() and Release().
+//  - Class with AddRef() and Release()
+//  - Class without AddRef() and Release()
+//  - Derived Class with AddRef() and Release()
+//  - Derived Class without AddRef() and Release()
+//  - Derived Class with AddRef() and Release() and a private destructor.
 TEST_F(BindTest, SupportsAddRefAndRelease) {
   EXPECT_TRUE(internal::SupportsAddRefAndRelease<HasRef>::value);
   EXPECT_FALSE(internal::SupportsAddRefAndRelease<NoRef>::value);
@@ -434,6 +444,10 @@ TEST_F(BindTest, SupportsAddRefAndRelease) {
   // inheritance.
   EXPECT_TRUE(internal::SupportsAddRefAndRelease<StrictMock<HasRef> >::value);
   EXPECT_FALSE(internal::SupportsAddRefAndRelease<StrictMock<NoRef> >::value);
+
+  // This matters because the implementation creates a dummy class that
+  // inherits from the template type.
+  EXPECT_TRUE(internal::SupportsAddRefAndRelease<HasRefPrivateDtor>::value);
 }
 
 // Unretained() wrapper support.