Support dragging a virtual file out of the browser.

app/os_exchange_data.h

Index: app/os_exchange_data.h
===================================================================
--- app/os_exchange_data.h	(revision 35459)
+++ app/os_exchange_data.h	(working copy)
@@ -18,6 +18,8 @@
 #endif
 
 #include "base/basictypes.h"
+#include "base/file_path.h"
+#include "base/ref_counted.h"
 #include "base/scoped_ptr.h"
 
 class GURL;
@@ -59,6 +61,48 @@
 #endif
   };
 
+  struct DownloadFileInfo;
+
+  // Defines the interface to observe the status of file download.
+  class DownloadFileObserver : public base::RefCounted<DownloadFileObserver> {
+   public:
+    // The caller is responsible to free the DownloadFileInfo objects passed
+    // in the vector parameter.
+    virtual void OnDataReady(
+        int format,
+        const std::vector<DownloadFileInfo*>& downloads) = 0;
+
+   protected:
+    friend class base::RefCounted<DownloadFileObserver>;
+    virtual ~DownloadFileObserver() {}
+  };
+
+  // Defines the interface to control how a file is downloaded.
+  class DownloadFileProvider :
+      public base::RefCountedThreadSafe<DownloadFileProvider> {
+   public:
+    virtual bool Start(DownloadFileObserver* observer, int format) = 0;
+    virtual void Stop() = 0;
+
+   protected:
+    friend class base::RefCountedThreadSafe<DownloadFileProvider>;
+    virtual ~DownloadFileProvider() {}
+  };
+
+  // Encapsulates the info about a file to be downloaded.
+  struct DownloadFileInfo {
+    FilePath filename;
+    uint64 size;
+    scoped_refptr<DownloadFileProvider> downloader;
+
+    DownloadFileInfo(const FilePath& filename,
+                     uint64 size,
+                     DownloadFileProvider* downloader)
+        : filename(filename),
+          size(size),
+          downloader(downloader) {}
+  };
+
   // Provider defines the platform specific part of OSExchangeData that
   // interacts with the native system.
   class Provider {
@@ -91,6 +135,7 @@
     virtual bool GetHtml(std::wstring* html, GURL* base_url) const = 0;
     virtual bool HasFileContents() const = 0;
     virtual bool HasHtml() const = 0;
+    virtual void SetDownloadFileInfo(DownloadFileInfo* download) = 0;
 #endif
   };
 
@@ -164,6 +209,9 @@
   bool GetFileContents(std::wstring* filename,
                        std::string* file_contents) const;
   bool GetHtml(std::wstring* html, GURL* base_url) const;
+
+  // Adds a download file with full path (CF_HDROP).
+  void SetDownloadFileInfo(DownloadFileInfo* download);
 #endif
 
  private: