Fix some issues found looking at the code. I have made two posts about it:...

base/base_drop_target.cc

 // Copyright (c) 2006-2008 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 <windows.h>
 #include <shlobj.h>
 
 #include "base/base_drop_target.h"
 
 #include "base/logging.h"
 
 ///////////////////////////////////////////////////////////////////////////////
 
 IDropTargetHelper* BaseDropTarget::cached_drop_target_helper_ = NULL;
 
 BaseDropTarget::BaseDropTarget(HWND hwnd)
-    : suspend_(false),
-      ref_count_(0),
-      hwnd_(hwnd) {
+    : current_data_object_(),
+      hwnd_(hwnd),
+      suspend_(false),
+      ref_count_(0) {
   DCHECK(hwnd);
   HRESULT result = RegisterDragDrop(hwnd, this);
+  DCHECK(SUCCEEDED(result));
 }
 
 BaseDropTarget::~BaseDropTarget() {
 }
 
 // static
 IDropTargetHelper* BaseDropTarget::DropHelper() {
   if (!cached_drop_target_helper_) {
     CoCreateInstance(CLSID_DragDropHelper, 0, CLSCTX_INPROC_SERVER,
                      IID_IDropTargetHelper,
@@ skipping 91 matching lines @@
   AddRef();
   return S_OK;
 }
 
 ULONG BaseDropTarget::AddRef() {
   return InterlockedIncrement(&ref_count_);
 }
 
 ULONG BaseDropTarget::Release() {
   if (InterlockedDecrement(&ref_count_) == 0) {
-    ULONG copied_refcnt = ref_count_;
     delete this;
-    return copied_refcnt;
+    return 0U;
   }
   return ref_count_;
 }
 
 DWORD BaseDropTarget::OnDragEnter(IDataObject* data_object,
                                   DWORD key_state,
                                   POINT cursor_position,
                                   DWORD effect) {
   return DROPEFFECT_NONE;
 }
 
 DWORD BaseDropTarget::OnDragOver(IDataObject* data_object,
                                  DWORD key_state,
                                  POINT cursor_position,
                                  DWORD effect) {
   return DROPEFFECT_NONE;
 }
 
 void BaseDropTarget::OnDragLeave(IDataObject* data_object) {
 }
 
 DWORD BaseDropTarget::OnDrop(IDataObject* data_object,
                              DWORD key_state,
                              POINT cursor_position,
                              DWORD effect) {
   return DROPEFFECT_NONE;
 }