Fix deadlock between UI thread and drag and drop thread on Windows.

ui/base/dragdrop/os_exchange_data_provider_win.h

 // Copyright (c) 2012 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 UI_BASE_DRAGDROP_OS_EXCHANGE_DATA_PROVIDER_WIN_H_
 #define UI_BASE_DRAGDROP_OS_EXCHANGE_DATA_PROVIDER_WIN_H_
 
 #include <objidl.h>
 #include <shlobj.h>
 #include <string>
@@ skipping 23 matching lines @@
     virtual void OnWaitForData() = 0;
     virtual void OnDataObjectDisposed() = 0;
    protected:
     virtual ~Observer() { }
   };
 
   DataObjectImpl();
 
   // Accessors.
   void set_observer(Observer* observer) { observer_ = observer; }
+  void set_in_drag_loop(bool in_drag_loop) { in_drag_loop_ = in_drag_loop; }
 
   // Number of known formats.
   size_t size() const { return contents_.size(); }
 
   // DownloadFileObserver implementation:
   virtual void OnDownloadCompleted(const base::FilePath& file_path);
   virtual void OnDownloadAborted();
 
   // IDataObject implementation:
   HRESULT __stdcall GetData(FORMATETC* format_etc, STGMEDIUM* medium);
@@ skipping 33 matching lines @@
   void StopDownloads();
 
   // Removes from contents_ the first data that matches |format|.
   void RemoveData(const FORMATETC& format);
 
   // Our internal representation of stored data & type info.
   struct StoredDataInfo {
     FORMATETC format_etc;
     STGMEDIUM* medium;
     bool owns_medium;
-    bool in_delay_rendering;
     scoped_refptr<DownloadFileProvider> downloader;
 
     StoredDataInfo(CLIPFORMAT cf, STGMEDIUM* medium)
         : medium(medium),
-          owns_medium(true),
-          in_delay_rendering(false) {
+          owns_medium(true) {
       format_etc.cfFormat = cf;
       format_etc.dwAspect = DVASPECT_CONTENT;
       format_etc.lindex = -1;
       format_etc.ptd = NULL;
       format_etc.tymed = medium ? medium->tymed : TYMED_HGLOBAL;
     }
 
     StoredDataInfo(FORMATETC* format_etc, STGMEDIUM* medium)
         : format_etc(*format_etc),
           medium(medium),
-          owns_medium(true),
-          in_delay_rendering(false) {
+          owns_medium(true) {
     }
 
     ~StoredDataInfo() {
       if (owns_medium) {
         ReleaseStgMedium(medium);
         delete medium;
       }
       if (downloader.get())
         downloader->Stop();
     }
   };
 
   typedef std::vector<StoredDataInfo*> StoredData;
   StoredData contents_;
 
   base::win::ScopedComPtr<IDataObject> source_object_;
 
   bool is_aborting_;
+  bool in_drag_loop_;
   bool in_async_mode_;
   bool async_operation_started_;
   Observer* observer_;
 };
 
 class UI_EXPORT OSExchangeDataProviderWin : public OSExchangeData::Provider {
  public:
   // Returns true if source has plain text that is a valid url.
   static bool HasPlainTextURL(IDataObject* source);
 
@@ skipping 37 matching lines @@
                                std::string* file_contents) const;
   virtual bool GetHtml(string16* html, GURL* base_url) const;
   virtual bool HasString() const;
   virtual bool HasURL() const;
   virtual bool HasFile() const;
   virtual bool HasFileContents() const;
   virtual bool HasHtml() const;
   virtual bool HasCustomFormat(OSExchangeData::CustomFormat format) const;
   virtual void SetDownloadFileInfo(
       const OSExchangeData::DownloadFileInfo& download_info);
+  virtual void SetInDragLoop(bool in_drag_loop) OVERRIDE;
 #if defined(USE_AURA)
   virtual void SetDragImage(const gfx::ImageSkia& image,
                             const gfx::Vector2d& cursor_offset) OVERRIDE;
   virtual const gfx::ImageSkia& GetDragImage() const OVERRIDE;
   virtual const gfx::Vector2d& GetDragImageOffset() const OVERRIDE;
 #endif
 
  private:
   scoped_refptr<DataObjectImpl> data_;
   base::win::ScopedComPtr<IDataObject> source_object_;
 
 #if defined(USE_AURA)
   // Drag image and offset data. Only used for Ash.
   gfx::ImageSkia drag_image_;
   gfx::Vector2d drag_image_offset_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(OSExchangeDataProviderWin);
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_DRAGDROP_OS_EXCHANGE_DATA_PROVIDER_WIN_H_