Lazily create the clipboard owner window. CreateWindow can take ~.5ms, and w...

base/clipboard_win.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.
 
 // Many of these functions are based on those found in
 // webkit/port/platform/PasteboardWin.cpp
 
 #include <shlobj.h>
 #include <shellapi.h>
 
@@ skipping 113 matching lines @@
 
 Clipboard::Clipboard() {
   // make a dummy HWND to be the clipboard's owner
   WNDCLASSEX wcex = {0};
   wcex.cbSize = sizeof(WNDCLASSEX);
   wcex.lpfnWndProc = ClipboardOwnerWndProc;
   wcex.hInstance = GetModuleHandle(NULL);
   wcex.lpszClassName = L"ClipboardOwnerWindowClass";
   ::RegisterClassEx(&wcex);
 
-  clipboard_owner_ = ::CreateWindow(L"ClipboardOwnerWindowClass",
-                                    L"ClipboardOwnerWindow",
-                                    0, 0, 0, 0, 0,
-                                    HWND_MESSAGE,
-                                    0, 0, 0);
+  clipboard_owner_ = NULL;
 }
 
 Clipboard::~Clipboard() {
-  ::DestroyWindow(clipboard_owner_);
+  if (clipboard_owner_)
+    ::DestroyWindow(clipboard_owner_);
   clipboard_owner_ = NULL;
 }
 
 void Clipboard::WriteObjects(const ObjectMap& objects) {
   WriteObjects(objects, NULL);
 }
 
 void Clipboard::WriteObjects(const ObjectMap& objects,
                              base::ProcessHandle process) {
   ScopedClipboard clipboard;
-  if (!clipboard.Acquire(clipboard_owner_))
+  if (!clipboard.Acquire(GetClipboardWindow()))
     return;
 
   ::EmptyClipboard();
 
   for (ObjectMap::const_iterator iter = objects.begin();
        iter != objects.end(); ++iter) {
     if (iter->first == CBF_SMBITMAP)
       WriteBitmapFromSharedMemory(&(iter->second[0].front()),
                                   &(iter->second[1].front()),
                                   process);
@@ skipping 214 matching lines @@
 void Clipboard::ReadText(std::wstring* result) const {
   if (!result) {
     NOTREACHED();
     return;
   }
 
   result->clear();
 
   // Acquire the clipboard.
   ScopedClipboard clipboard;
-  if (!clipboard.Acquire(clipboard_owner_))
+  if (!clipboard.Acquire(GetClipboardWindow()))
     return;
 
   HANDLE data = ::GetClipboardData(CF_UNICODETEXT);
   if (!data)
     return;
 
   result->assign(static_cast<const wchar_t*>(::GlobalLock(data)));
   ::GlobalUnlock(data);
 }
 
 void Clipboard::ReadAsciiText(std::string* result) const {
   if (!result) {
     NOTREACHED();
     return;
   }
 
   result->clear();
 
   // Acquire the clipboard.
   ScopedClipboard clipboard;
-  if (!clipboard.Acquire(clipboard_owner_))
+  if (!clipboard.Acquire(GetClipboardWindow()))
     return;
 
   HANDLE data = ::GetClipboardData(CF_TEXT);
   if (!data)
     return;
 
   result->assign(static_cast<const char*>(::GlobalLock(data)));
   ::GlobalUnlock(data);
 }
 
 void Clipboard::ReadHTML(std::wstring* markup, std::string* src_url) const {
   if (markup)
     markup->clear();
 
   if (src_url)
     src_url->clear();
 
   // Acquire the clipboard.
   ScopedClipboard clipboard;
-  if (!clipboard.Acquire(clipboard_owner_))
+  if (!clipboard.Acquire(GetClipboardWindow()))
     return;
 
   HANDLE data = ::GetClipboardData(GetHtmlFormatType());
   if (!data)
     return;
 
   std::string html_fragment(static_cast<const char*>(::GlobalLock(data)));
   ::GlobalUnlock(data);
 
   std::string markup_utf8;
   ClipboardUtil::CFHtmlToHtml(html_fragment, &markup_utf8, src_url);
   markup->assign(UTF8ToWide(markup_utf8));
 }
 
 void Clipboard::ReadBookmark(std::wstring* title, std::string* url) const {
   if (title)
     title->clear();
 
   if (url)
     url->clear();
 
   // Acquire the clipboard.
   ScopedClipboard clipboard;
-  if (!clipboard.Acquire(clipboard_owner_))
+  if (!clipboard.Acquire(GetClipboardWindow()))
     return;
 
   HANDLE data = ::GetClipboardData(GetUrlWFormatType());
   if (!data)
     return;
 
   std::wstring bookmark(static_cast<const wchar_t*>(::GlobalLock(data)));
   ::GlobalUnlock(data);
 
   ParseBookmarkClipboardFormat(bookmark, title, url);
@@ skipping 18 matching lines @@
 // Read a set of files in HDROP format from the clipboard.
 void Clipboard::ReadFiles(std::vector<std::wstring>* files) const {
   if (!files) {
     NOTREACHED();
     return;
   }
 
   files->clear();
 
   ScopedClipboard clipboard;
-  if (!clipboard.Acquire(clipboard_owner_))
+  if (!clipboard.Acquire(GetClipboardWindow()))
     return;
 
   HDROP drop = static_cast<HDROP>(::GetClipboardData(CF_HDROP));
   if (!drop)
     return;
 
   // Count of files in the HDROP.
   int count = ::DragQueryFile(drop, 0xffffffff, NULL, 0);
 
   if (count) {
@@ skipping 95 matching lines @@
   return ClipboardUtil::GetWebKitSmartPasteFormat()->cfFormat;
 }
 
 // static
 void Clipboard::FreeData(FormatType format, HANDLE data) {
   if (format == CF_BITMAP)
     ::DeleteObject(static_cast<HBITMAP>(data));
   else
     ::GlobalFree(data);
 }
+
+HWND Clipboard::GetClipboardWindow() const {
+  if (!clipboard_owner_) {
+    clipboard_owner_ = ::CreateWindow(L"ClipboardOwnerWindowClass",
+                                      L"ClipboardOwnerWindow",
+                                      0, 0, 0, 0, 0,
+                                      HWND_MESSAGE,
+                                      0, 0, 0);
+  }
+  return clipboard_owner_;
+}