Have ScopedClipboardWriter and Clipboard::WriteObjects take a buffer parameter.

ui/base/clipboard/clipboard.h

Index: ui/base/clipboard/clipboard.h
diff --git a/ui/base/clipboard/clipboard.h b/ui/base/clipboard/clipboard.h
index 4dc7a380557640a94b1d6cf426d6712104a1987a..0182c65a877b72472cf164c43ed26626c3add927 100644
--- a/ui/base/clipboard/clipboard.h
+++ b/ui/base/clipboard/clipboard.h
@@ -130,9 +130,7 @@ class UI_EXPORT Clipboard {
 
   // Buffer designates which clipboard the action should be applied to.
   // Only platforms that use the X Window System support the selection
-  // buffer. Furthermore we currently only use a buffer other than the
-  // standard buffer when reading from the clipboard so only those
-  // functions accept a buffer parameter.
+  // buffer.
   enum Buffer {
     BUFFER_STANDARD,
     BUFFER_SELECTION,
@@ -161,14 +159,14 @@ class UI_EXPORT Clipboard {
   // contents of |objects|. On Windows they are copied to the system clipboard.
   // On linux they are copied into a structure owned by the Clipboard object and
   // kept until the system clipboard is set again.
-  void WriteObjects(const ObjectMap& objects);
+  void WriteObjects(Buffer buffer, const ObjectMap& objects);
 
   // On Linux/BSD, we need to know when the clipboard is set to a URL.  Most
   // platforms don't care.
 #if defined(OS_WIN) || defined(OS_MACOSX) || defined(USE_AURA)
-  void DidWriteURL(const std::string& utf8_text) {}
+  void DidWriteURL(Buffer buffer, const std::string& utf8_text) {}

[dcheng, 2012/02/03 21:53:58]

It seems like we don't need the buffer parameter since it only applies when we
write to the standard selection (e.g. the pasteboard).

[peter1, 2012/02/04 00:54:46]

We need to check in DidWriteURL that the write was to the clipboard to avoid
overwriting the just-written (and possibly multi-format) primary selection with
a plain text URL, and for that we need the buffer parameter.

[dcheng, 2012/02/04 01:11:05]

Right, but this is only called from ScopedClipboardWriter (and not
ScopedClipboardWriterGlue). ScopedClipboardWriter already knows which buffer
it's writing to, so it can skip the call there can't it?

[peter1, 2012/02/04 02:05:43]

I see.  Well, I don't think it matters too much where we do this test, so I'll
go ahead and move it.

 #else  // !defined(OS_WIN) && !defined(OS_MACOSX)
-  void DidWriteURL(const std::string& utf8_text);
+  void DidWriteURL(Buffer buffer, const std::string& utf8_text);
 #endif
 
   // Returns a sequence number which uniquely identifies clipboard state.
@@ -311,7 +309,7 @@ class UI_EXPORT Clipboard {
 
  private:
   // Write changes to gtk clipboard.
-  void SetGtkClipboard();
+  void SetGtkClipboard(Buffer buffer);
   // Insert a mapping into clipboard_data_.
   void InsertMapping(const char* key, char* data, size_t data_len);