net: Add NET_API to net/base

BUG=76997
TEST=NONE
Review URL: http://codereview.chromium.org/6969077

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@85785 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 23 insertions, 1 deletions

diff --git a/base/compiler_specific.h b/base/compiler_specific.h
index 43ff21c..99e4f8e 100644
--- a/base/compiler_specific.h
+++ b/base/compiler_specific.h
@@ -54,6 +54,21 @@
                                              code \
                                              MSVC_POP_WARNING()
 
+// Allows exporting a class that inherits from a non-exported base class.
+// This uses suppress instead of push/pop because the delimiter after the
+// declaration (either "," or "{") has to be placed before the pop macro.
+//
+// Example usage:
+// class EXPORT_API Foo : NON_EXPORTED_BASE(public Bar) {
+//
+// MSVC Compiler warning C4275:
+// non dll-interface class 'Bar' used as base for dll-interface class 'Foo'.
+// Note that this is intended to be used only when no access to the base class
+// can be gained through the derived class. For more info, see
+// http://msdn.microsoft.com/en-us/library/3tdb471s(VS.80).aspx
+#define NON_EXPORTED_BASE(code) MSVC_SUPPRESS_WARNING(4275) \
+                                code
+
 #else  // Not MSVC
 
 #define MSVC_SUPPRESS_WARNING(n)
@@ -63,6 +78,7 @@
 #define MSVC_DISABLE_OPTIMIZE()
 #define MSVC_ENABLE_OPTIMIZE()
 #define ALLOW_THIS_IN_INITIALIZER_LIST(code) code
+#define NON_EXPORTED_BASE(code) code
 
 #endif  // COMPILER_MSVC
 
diff --git a/base/threading/non_thread_safe.h b/base/threading/non_thread_safe.h
index e4a1c07..3f60fed 100644
--- a/base/threading/non_thread_safe.h
+++ b/base/threading/non_thread_safe.h
@@ -6,6 +6,12 @@
 #define BASE_THREADING_NON_THREAD_SAFE_H_
 #pragma once
 
+// Classes deriving from NonThreadSafe may need to supress MSVC warning 4275:
+// non dll-interface class 'Bar' used as base for dll-interface class 'Foo'.
+// There is a specific macro to do it: NON_EXPORTED_BASE(), defined in
+// compiler_specific.h
+#include "base/compiler_specific.h"
+
 #ifndef NDEBUG
 #include "base/threading/non_thread_safe_impl.h"
 #endif
diff --git a/base/win/object_watcher.h b/base/win/object_watcher.h
index 0eef022..4cc6090 100644
--- a/base/win/object_watcher.h
+++ b/base/win/object_watcher.h
@@ -44,7 +44,7 @@ namespace win {
 //
 class BASE_API ObjectWatcher : public MessageLoop::DestructionObserver {
  public:
-  class Delegate {
+  class BASE_API Delegate {
    public:
     virtual ~Delegate() {}
     // Called from the MessageLoop when a signaled object is detected.  To