Support dragging a virtual file out of the browser.

BUG=none
TEST=none

Review URL: http://codereview.chromium.org/351029

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@36378 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 439 insertions, 79 deletions

diff --git a/chrome/browser/views/tab_contents/tab_contents_drag_win.cc b/chrome/browser/views/tab_contents/tab_contents_drag_win.cc
new file mode 100644
index 0000000..a507c6c
--- /dev/null
+++ b/chrome/browser/views/tab_contents/tab_contents_drag_win.cc
@@ -0,0 +1,328 @@
+// 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.
+
+#include "chrome/browser/views/tab_contents/tab_contents_drag_win.h"
+
+#include <windows.h>
+
+#include "base/file_path.h"
+#include "base/message_loop.h"
+#include "base/task.h"
+#include "base/thread.h"
+#include "base/win_util.h"
+#include "chrome/browser/bookmarks/bookmark_drag_data.h"
+#include "chrome/browser/chrome_thread.h"
+#include "chrome/browser/download/drag_download_file_win.h"
+#include "chrome/browser/profile.h"
+#include "chrome/browser/tab_contents/tab_contents.h"
+#include "chrome/browser/tab_contents/web_drag_source_win.h"
+#include "chrome/browser/tab_contents/web_drop_target_win.h"
+#include "chrome/browser/views/tab_contents/tab_contents_view_win.h"
+#include "chrome/common/url_constants.h"
+#include "net/base/net_util.h"
+#include "webkit/glue/webdropdata.h"
+
+using WebKit::WebDragOperationsMask;
+
+namespace {
+
+HHOOK msg_hook = NULL;
+DWORD drag_out_thread_id = 0;
+bool mouse_up_received = false;
+
+LRESULT CALLBACK MsgFilterProc(int code, WPARAM wparam, LPARAM lparam) {
+  if (code == base::MessagePumpForUI::kMessageFilterCode &&
+      !mouse_up_received) {
+    MSG* msg = reinterpret_cast<MSG*>(lparam);
+    // We do not care about WM_SYSKEYDOWN and WM_SYSKEYUP because when ALT key
+    // is pressed down on drag-and-drop, it means to create a link.
+    if (msg->message == WM_MOUSEMOVE || msg->message == WM_LBUTTONUP ||
+        msg->message == WM_KEYDOWN || msg->message == WM_KEYUP) {
+      // Forward the message from the UI thread to the drag-and-drop thread.
+      PostThreadMessage(drag_out_thread_id,
+                        msg->message,
+                        msg->wParam,
+                        msg->lParam);
+
+      // If the left button is up, we do not need to forward the message any
+      // more.
+      if (msg->message == WM_LBUTTONUP || !(GetKeyState(VK_LBUTTON) & 0x8000))
+        mouse_up_received = true;
+
+      return TRUE;
+    }
+  }
+  return CallNextHookEx(msg_hook, code, wparam, lparam);
+}
+
+}  // namespace
+
+class DragDropThread : public base::Thread {
+ public:
+  explicit DragDropThread(TabContentsDragWin* drag_handler)
+       : base::Thread("Chrome_DragDropThread"),
+         drag_handler_(drag_handler) {
+  }
+
+  virtual ~DragDropThread() {
+    Thread::Stop();
+  }
+
+ protected:
+  // base::Thread implementations:
+  virtual void Init() {
+    int ole_result = OleInitialize(NULL);
+    DCHECK(ole_result == S_OK);
+  }
+
+  virtual void CleanUp() {
+    OleUninitialize();
+  }
+
+ private:
+  // Hold a reference count to TabContentsDragWin to make sure that it is always
+  // alive in the thread lifetime.
+  scoped_refptr<TabContentsDragWin> drag_handler_;
+
+  DISALLOW_COPY_AND_ASSIGN(DragDropThread);
+};
+
+TabContentsDragWin::TabContentsDragWin(TabContentsViewWin* view)
+    : view_(view),
+      drag_ended_(false),
+      old_drop_target_suspended_state_(false) {
+#ifndef NDEBUG
+  drag_drop_thread_id_ = 0;
+#endif
+}
+
+TabContentsDragWin::~TabContentsDragWin() {
+  DCHECK(ChromeThread::CurrentlyOn(ChromeThread::UI));
+  DCHECK(!drag_source_.get());
+  DCHECK(!drag_drop_thread_.get());
+}
+
+void TabContentsDragWin::StartDragging(const WebDropData& drop_data,
+                                       WebDragOperationsMask ops) {
+  DCHECK(ChromeThread::CurrentlyOn(ChromeThread::UI));
+
+  drag_source_ = new WebDragSource(view_->GetNativeView(),
+                                   view_->tab_contents());
+
+  const GURL& page_url = view_->tab_contents()->GetURL();
+  const std::string& page_encoding = view_->tab_contents()->encoding();
+
+  // If it is not drag-out, do the drag-and-drop in the current UI thread.
+  if (!drop_data.download_url.is_valid()) {
+    DoDragging(drop_data, ops, page_url, page_encoding);
+    EndDragging(false);
+    return;
+  }
+
+  // We do not want to drag and drop the download to itself.
+  old_drop_target_suspended_state_ = view_->drop_target()->suspended();
+  view_->drop_target()->set_suspended(true);
+
+  // Start a background thread to do the drag-and-drop.
+  DCHECK(!drag_drop_thread_.get());
+  drag_drop_thread_.reset(new DragDropThread(this));
+  base::Thread::Options options;
+  options.message_loop_type = MessageLoop::TYPE_UI;
+  if (drag_drop_thread_->StartWithOptions(options)) {
+    drag_drop_thread_->message_loop()->PostTask(
+        FROM_HERE,
+        NewRunnableMethod(this,
+                          &TabContentsDragWin::StartBackgroundDragging,
+                          drop_data,
+                          ops,
+                          page_url,
+                          page_encoding));
+  }
+
+  // Install a hook procedure to monitor the messages so that we can forward
+  // the appropriate ones to the background thread.
+  drag_out_thread_id = drag_drop_thread_->thread_id();
+  mouse_up_received = false;
+  DCHECK(!msg_hook);
+  msg_hook = SetWindowsHookEx(WH_MSGFILTER,
+                              MsgFilterProc,
+                              NULL,
+                              GetCurrentThreadId());
+
+  // Attach the input state of the background thread to the UI thread so that
+  // SetCursor can work from the background thread.
+  AttachThreadInput(drag_out_thread_id, GetCurrentThreadId(), TRUE);
+}
+
+void TabContentsDragWin::StartBackgroundDragging(
+    const WebDropData& drop_data,
+    WebDragOperationsMask ops,
+    const GURL& page_url,
+    const std::string& page_encoding) {
+#ifndef NDEBUG
+  drag_drop_thread_id_ = PlatformThread::CurrentId();
+#endif
+
+  DoDragging(drop_data, ops, page_url, page_encoding);
+  ChromeThread::PostTask(
+      ChromeThread::UI, FROM_HERE,
+      NewRunnableMethod(this, &TabContentsDragWin::EndDragging, true));
+}
+
+void TabContentsDragWin::PrepareDragForDownload(
+    const WebDropData& drop_data,
+    OSExchangeData* data,
+    const GURL& page_url,
+    const std::string& page_encoding) {
+  // Provide the data as file (CF_HDROP). A temporary download file with the
+  // Zone.Identifier ADS (Alternate Data Stream) attached will be created.
+  scoped_refptr<DragDownloadFile> download_file =
+      new DragDownloadFile(drop_data.download_url,
+                           page_url,
+                           page_encoding,
+                           view_->tab_contents());
+  OSExchangeData::DownloadFileInfo* file_download =
+      new OSExchangeData::DownloadFileInfo(FilePath(),
+                                           0,
+                                           download_file.get());
+  data->SetDownloadFileInfo(file_download);
+
+  // Enable asynchronous operation.
+  OSExchangeDataProviderWin::GetIAsyncOperation(*data)->SetAsyncMode(TRUE);
+}
+
+void TabContentsDragWin::PrepareDragForFileContents(
+    const WebDropData& drop_data, OSExchangeData* data) {
+  // Images without ALT text will only have a file extension so we need to
+  // synthesize one from the provided extension and URL.
+  FilePath file_name(drop_data.file_description_filename);
+  file_name = file_name.BaseName().RemoveExtension();
+  if (file_name.value().empty()) {
+    // Retrieve the name from the URL.
+    file_name = net::GetSuggestedFilename(drop_data.url, "", "", FilePath());
+    if (file_name.value().size() + drop_data.file_extension.size() + 1 >
+        MAX_PATH) {
+      file_name = FilePath(file_name.value().substr(
+          0, MAX_PATH - drop_data.file_extension.size() - 2));
+    }
+  }
+  file_name = file_name.ReplaceExtension(drop_data.file_extension);
+  data->SetFileContents(file_name.value(), drop_data.file_contents);
+}
+
+void TabContentsDragWin::PrepareDragForUrl(const WebDropData& drop_data,
+                                           OSExchangeData* data) {
+  if (drop_data.url.SchemeIs(chrome::kJavaScriptScheme)) {
+    // We don't want to allow javascript URLs to be dragged to the desktop,
+    // but we do want to allow them to be added to the bookmarks bar
+    // (bookmarklets). So we create a fake bookmark entry (BookmarkDragData
+    // object) which explorer.exe cannot handle, and write the entry to data.
+    BookmarkDragData::Element bm_elt;
+    bm_elt.is_url = true;
+    bm_elt.url = drop_data.url;
+    bm_elt.title = drop_data.url_title;
+
+    BookmarkDragData bm_drag_data;
+    bm_drag_data.elements.push_back(bm_elt);
+
+    // Pass in NULL as the profile so that the bookmark always adds the url
+    // rather than trying to move an existing url.
+    bm_drag_data.Write(NULL, data);
+  } else {
+    data->SetURL(drop_data.url, drop_data.url_title);
+  }
+}
+
+void TabContentsDragWin::DoDragging(const WebDropData& drop_data,
+                                    WebDragOperationsMask ops,
+                                    const GURL& page_url,
+                                    const std::string& page_encoding) {
+  OSExchangeData data;
+
+  // TODO(tc): Generate an appropriate drag image.
+
+  if (drop_data.download_url.is_valid()) {
+    PrepareDragForDownload(drop_data, &data, page_url, page_encoding);
+
+    // Set the observer.
+    OSExchangeDataProviderWin::GetDataObjectImpl(data)->set_observer(this);
+  } else {
+    // We set the file contents before the URL because the URL also sets file
+    // contents (to a .URL shortcut).  We want to prefer file content data over
+    // a shortcut so we add it first.
+    if (!drop_data.file_contents.empty())
+      PrepareDragForFileContents(drop_data, &data);
+    if (!drop_data.text_html.empty())
+      data.SetHtml(drop_data.text_html, drop_data.html_base_url);
+    if (drop_data.url.is_valid())
+      PrepareDragForUrl(drop_data, &data);
+    if (!drop_data.plain_text.empty())
+      data.SetString(drop_data.plain_text);
+  }
+
+  DWORD effects = 0;
+
+  // We need to enable recursive tasks on the message loop so we can get
+  // updates while in the system DoDragDrop loop.
+  bool old_state = MessageLoop::current()->NestableTasksAllowed();
+  MessageLoop::current()->SetNestableTasksAllowed(true);
+  DoDragDrop(OSExchangeDataProviderWin::GetIDataObject(data), drag_source_,
+             DROPEFFECT_COPY | DROPEFFECT_LINK, &effects);
+  // TODO(snej): Use 'ops' param instead of hardcoding dropeffects
+  MessageLoop::current()->SetNestableTasksAllowed(old_state);
+}
+
+void TabContentsDragWin::EndDragging(bool restore_suspended_state) {
+  DCHECK(ChromeThread::CurrentlyOn(ChromeThread::UI));
+
+  if (drag_ended_)
+    return;
+  drag_ended_ = true;
+
+  if (restore_suspended_state)
+    view_->drop_target()->set_suspended(old_drop_target_suspended_state_);
+
+  drag_source_ = NULL;
+
+  if (msg_hook) {
+    AttachThreadInput(drag_out_thread_id, GetCurrentThreadId(), FALSE);
+    UnhookWindowsHookEx(msg_hook);
+    msg_hook = NULL;
+  }
+
+  view_->EndDragging();
+}
+
+void TabContentsDragWin::CancelDrag() {
+  DCHECK(ChromeThread::CurrentlyOn(ChromeThread::UI));
+
+  drag_source_->CancelDrag();
+}
+
+void TabContentsDragWin::CloseThread() {
+  DCHECK(ChromeThread::CurrentlyOn(ChromeThread::UI));
+
+  drag_drop_thread_.reset();
+}
+
+void TabContentsDragWin::OnWaitForData() {
+  DCHECK(drag_drop_thread_id_ == PlatformThread::CurrentId());
+
+  // When the left button is release and we start to wait for the data, end
+  // the dragging before DoDragDrop returns. This makes the page leave the drag
+  // mode so that it can start to process the normal input events.
+  ChromeThread::PostTask(
+      ChromeThread::UI, FROM_HERE,
+      NewRunnableMethod(this, &TabContentsDragWin::EndDragging, true));
+}
+
+void TabContentsDragWin::OnDataObjectDisposed() {
+  DCHECK(drag_drop_thread_id_ == PlatformThread::CurrentId());
+
+  // The drag-and-drop thread is only closed after OLE is done with
+  // DataObjectImpl.
+  ChromeThread::PostTask(
+      ChromeThread::UI, FROM_HERE,
+      NewRunnableMethod(this, &TabContentsDragWin::CloseThread));
+}
diff --git a/chrome/browser/views/tab_contents/tab_contents_drag_win.h b/chrome/browser/views/tab_contents/tab_contents_drag_win.h
new file mode 100644
index 0000000..5fbddd9
--- /dev/null
+++ b/chrome/browser/views/tab_contents/tab_contents_drag_win.h
@@ -0,0 +1,93 @@
+// 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.
+
+#ifndef CHROME_BROWSER_VIEWS_TAB_CONTENTS_TAB_CONTENTS_DRAG_WIN_H_
+#define CHROME_BROWSER_VIEWS_TAB_CONTENTS_TAB_CONTENTS_DRAG_WIN_H_
+
+#include "app/os_exchange_data_provider_win.h"
+#include "base/platform_thread.h"
+#include "base/ref_counted.h"
+#include "base/scoped_ptr.h"
+#include "third_party/WebKit/WebKit/chromium/public/WebDragOperation.h"
+
+class DragDropThread;
+class TabContentsViewWin;
+class WebDragSource;
+struct WebDropData;
+
+// Windows-specific drag-and-drop handling in TabContentsView.
+// If we are dragging a virtual file out of the browser, we use a background
+// thread to do the drag-and-drop because we do not want to run nested
+// message loop in the UI thread. For all other cases, the drag-and-drop happens
+// in the UI thread.
+class TabContentsDragWin
+    : public DataObjectImpl::Observer,
+      public base::RefCountedThreadSafe<TabContentsDragWin> {
+ public:
+  explicit TabContentsDragWin(TabContentsViewWin* view);
+  virtual ~TabContentsDragWin();
+
+  // Called on UI thread.
+  void StartDragging(const WebDropData& drop_data,
+                     WebKit::WebDragOperationsMask ops);
+  void CancelDrag();
+
+  // DataObjectImpl::Observer implementation.
+  // Called on drag-and-drop thread.
+  virtual void OnWaitForData();
+  virtual void OnDataObjectDisposed();
+
+ private:
+  // Called on either UI thread or drag-and-drop thread.
+  void PrepareDragForDownload(const WebDropData& drop_data,
+                              OSExchangeData* data,
+                              const GURL& page_url,
+                              const std::string& page_encoding);
+  void PrepareDragForFileContents(const WebDropData& drop_data,
+                                  OSExchangeData* data);
+  void PrepareDragForUrl(const WebDropData& drop_data, OSExchangeData* data);
+  void DoDragging(const WebDropData& drop_data,
+                  WebKit::WebDragOperationsMask ops,
+                  const GURL& page_url,
+                  const std::string& page_encoding);
+
+  // Called on drag-and-drop thread.
+  void StartBackgroundDragging(const WebDropData& drop_data,
+                               WebKit::WebDragOperationsMask ops,
+                               const GURL& page_url,
+                               const std::string& page_encoding);
+  // Called on UI thread.
+  void EndDragging(bool restore_suspended_state);
+  void CloseThread();
+
+  // For debug check only. Access only on drag-and-drop thread.
+#ifndef NDEBUG
+  PlatformThreadId drag_drop_thread_id_;
+#endif
+
+  // All the member variables below are accessed on UI thread.
+
+  // Keep track of the TabContentsViewWin it is associated with.
+  TabContentsViewWin* view_;
+
+  // |drag_source_| is our callback interface passed to the system when we
+  // want to initiate a drag and drop operation.  We use it to tell if a
+  // drag operation is happening.
+  scoped_refptr<WebDragSource> drag_source_;
+
+  // The thread used by the drag-out download. This is because we want to avoid
+  // running nested message loop in main UI thread.
+  scoped_ptr<DragDropThread> drag_drop_thread_;
+
+  // The flag to guard that EndDragging is not called twice.
+  bool drag_ended_;
+
+  // Keep track of the old suspended state of the drop target.
+  bool old_drop_target_suspended_state_;
+
+  DISALLOW_COPY_AND_ASSIGN(TabContentsDragWin);
+};
+
+
+#endif  // CHROME_BROWSER_VIEWS_TAB_CONTENTS_TAB_CONTENTS_DRAG_WIN_H_
diff --git a/chrome/browser/views/tab_contents/tab_contents_view_win.cc b/chrome/browser/views/tab_contents/tab_contents_view_win.cc
index a6f8b3e..f6bb820 100644
--- a/chrome/browser/views/tab_contents/tab_contents_view_win.cc
+++ b/chrome/browser/views/tab_contents/tab_contents_view_win.cc
@@ -8,12 +8,10 @@
 
 #include "app/gfx/canvas_paint.h"
 #include "app/os_exchange_data.h"
-#include "app/os_exchange_data_provider_win.h"
 #include "base/file_path.h"
 #include "base/keyboard_codes.h"
 #include "base/time.h"
 #include "base/win_util.h"
-#include "chrome/browser/bookmarks/bookmark_drag_data.h"
 #include "chrome/browser/browser.h"  // TODO(beng): this dependency is awful.
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/download/download_request_manager.h"
@@ -24,16 +22,13 @@
 #include "chrome/browser/tab_contents/interstitial_page.h"
 #include "chrome/browser/tab_contents/tab_contents.h"
 #include "chrome/browser/tab_contents/tab_contents_delegate.h"
-#include "chrome/browser/tab_contents/web_drag_source_win.h"
 #include "chrome/browser/tab_contents/web_drop_target_win.h"
 #include "chrome/browser/views/sad_tab_view.h"
 #include "chrome/browser/views/tab_contents/render_view_context_menu_win.h"
-#include "chrome/common/url_constants.h"
-#include "net/base/net_util.h"
+#include "chrome/browser/views/tab_contents/tab_contents_drag_win.h"
 #include "views/focus/view_storage.h"
 #include "views/screen.h"
 #include "views/widget/root_view.h"
-#include "webkit/glue/webdropdata.h"
 
 using WebKit::WebDragOperation;
 using WebKit::WebDragOperationNone;
@@ -62,8 +57,6 @@ TabContentsViewWin::~TabContentsViewWin() {
   views::ViewStorage* view_storage = views::ViewStorage::GetSharedInstance();
   if (view_storage->RetrieveView(last_focused_view_storage_id_) != NULL)
     view_storage->RemoveView(last_focused_view_storage_id_);
-
-  DCHECK(!drag_source_.get());
 }
 
 void TabContentsViewWin::Unparent() {
@@ -132,70 +125,11 @@ void TabContentsViewWin::GetContainerBounds(gfx::Rect* out) const {
 
 void TabContentsViewWin::StartDragging(const WebDropData& drop_data,
                                        WebDragOperationsMask ops) {
-  OSExchangeData data;
-
-  // TODO(tc): Generate an appropriate drag image.
-
-  // We set the file contents before the URL because the URL also sets file
-  // contents (to a .URL shortcut).  We want to prefer file content data over a
-  // shortcut so we add it first.
-  if (!drop_data.file_contents.empty()) {
-    // Images without ALT text will only have a file extension so we need to
-    // synthesize one from the provided extension and URL.
-    FilePath file_name(drop_data.file_description_filename);
-    file_name = file_name.BaseName().RemoveExtension();
-    if (file_name.value().empty()) {
-      // Retrieve the name from the URL.
-      file_name = net::GetSuggestedFilename(drop_data.url, "", "", FilePath());
-      if (file_name.value().size() + drop_data.file_extension.size() + 1 >
-          MAX_PATH) {
-        file_name = FilePath(file_name.value().substr(
-            0, MAX_PATH - drop_data.file_extension.size() - 2));
-      }
-    }
-    file_name = file_name.ReplaceExtension(drop_data.file_extension);
-    data.SetFileContents(file_name.value(), drop_data.file_contents);
-  }
-  if (!drop_data.text_html.empty())
-    data.SetHtml(drop_data.text_html, drop_data.html_base_url);
-  if (drop_data.url.is_valid()) {
-    if (drop_data.url.SchemeIs(chrome::kJavaScriptScheme)) {
-      // We don't want to allow javascript URLs to be dragged to the desktop,
-      // but we do want to allow them to be added to the bookmarks bar
-      // (bookmarklets). So we create a fake bookmark entry (BookmarkDragData
-      // object) which explorer.exe cannot handle, and write the entry to data.
-      BookmarkDragData::Element bm_elt;
-      bm_elt.is_url = true;
-      bm_elt.url = drop_data.url;
-      bm_elt.title = drop_data.url_title;
-
-      BookmarkDragData bm_drag_data;
-      bm_drag_data.elements.push_back(bm_elt);
-
-      // Pass in NULL as the profile so that the bookmark always adds the url
-      // rather than trying to move an existing url.
-      bm_drag_data.Write(NULL, &data);
-    } else {
-      data.SetURL(drop_data.url, drop_data.url_title);
-    }
-  }
-  if (!drop_data.plain_text.empty())
-    data.SetString(drop_data.plain_text);
-
-  drag_source_ = new WebDragSource(GetNativeView(), tab_contents());
-
-  DWORD effects;
-
-  // We need to enable recursive tasks on the message loop so we can get
-  // updates while in the system DoDragDrop loop.
-  bool old_state = MessageLoop::current()->NestableTasksAllowed();
-  MessageLoop::current()->SetNestableTasksAllowed(true);
-  DoDragDrop(OSExchangeDataProviderWin::GetIDataObject(data), drag_source_,
-             DROPEFFECT_COPY | DROPEFFECT_LINK, &effects);
-  // TODO(snej): Use 'ops' param instead of hardcoding dropeffects
-  MessageLoop::current()->SetNestableTasksAllowed(old_state);
+  drag_handler_ = new TabContentsDragWin(this);
+  drag_handler_->StartDragging(drop_data, ops);
+}
 
-  drag_source_ = NULL;
+void TabContentsViewWin::EndDragging() {
   if (close_tab_after_drag_ends_) {
     close_tab_timer_.Start(base::TimeDelta::FromMilliseconds(0), this,
                            &TabContentsViewWin::CloseTab);
@@ -203,6 +137,8 @@ void TabContentsViewWin::StartDragging(const WebDropData& drop_data,
 
   if (tab_contents()->render_view_host())
     tab_contents()->render_view_host()->DragSourceSystemDragEnded();
+
+  drag_handler_ = NULL;
 }
 
 void TabContentsViewWin::OnDestroy() {
@@ -328,15 +264,15 @@ void TabContentsViewWin::RestoreFocus() {
 }
 
 bool TabContentsViewWin::IsDoingDrag() const {
-  return drag_source_.get() != NULL;
+  return drag_handler_.get() != NULL;
 }
 
 void TabContentsViewWin::CancelDragAndCloseTab() {
   DCHECK(IsDoingDrag());
   // We can't close the tab while we're in the drag and
-  // |drag_source_->CancelDrag()| is async.  Instead, set a flag to cancel
+  // |drag_handler_->CancelDrag()| is async.  Instead, set a flag to cancel
   // the drag and when the drag nested message loop ends, close the tab.
-  drag_source_->CancelDrag();
+  drag_handler_->CancelDrag();
   close_tab_after_drag_ends_ = true;
 }
 
diff --git a/chrome/browser/views/tab_contents/tab_contents_view_win.h b/chrome/browser/views/tab_contents/tab_contents_view_win.h
index 5987baa..dc1e257 100644
--- a/chrome/browser/views/tab_contents/tab_contents_view_win.h
+++ b/chrome/browser/views/tab_contents/tab_contents_view_win.h
@@ -13,6 +13,7 @@
 
 class RenderViewContextMenuWin;
 class SadTabView;
+class TabContentsDragWin;
 struct WebDropData;
 class WebDragSource;
 class WebDropTarget;
@@ -62,6 +63,10 @@ class TabContentsViewWin : public TabContentsView,
   // WidgetWin overridde.
   virtual views::FocusManager* GetFocusManager();
 
+  void EndDragging();
+
+  WebDropTarget* drop_target() const { return drop_target_.get(); }
+
  private:
   // A helper method for closing the tab.
   void CloseTab();
@@ -118,11 +123,6 @@ class TabContentsViewWin : public TabContentsView,
   // accessible when unparented.
   views::FocusManager* focus_manager_;
 
-  // |drag_source_| is our callback interface passed to the system when we
-  // want to initiate a drag and drop operation.  We use it to tell if a
-  // drag operation is happening.
-  scoped_refptr<WebDragSource> drag_source_;
-
   // Set to true if we want to close the tab after the system drag operation
   // has finished.
   bool close_tab_after_drag_ends_;
@@ -130,6 +130,9 @@ class TabContentsViewWin : public TabContentsView,
   // Used to close the tab after the stack has unwound.
   base::OneShotTimer<TabContentsViewWin> close_tab_timer_;
 
+  // Used to handle the drag-and-drop.
+  scoped_refptr<TabContentsDragWin> drag_handler_;
+
   DISALLOW_COPY_AND_ASSIGN(TabContentsViewWin);
 };