Implement new Chromium IPCs for copying/dragging

Implement new Chromium IPCs for copying/dragging.

A new ClipboardDispatcher interface has been added to handle the IPC calls. The new methods don't really belong on the existing Clipboard class, since that class deals with only copy and paste. On Windows and Mac, ClipboardDispatcher will share logic for copy/paste and drag/drop. GTK will have to use two separate code paths.

BUG=31037
TEST=none

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=51790

[dcheng, 2010-07-02 02:56:14]

Just a couple stubs for now. To give an idea of what a ClipboardDispatcher
implementation might look like, a sample Win32 implementation might go like
this:
ScopedComPtr<IDataObject> data_object;
if (source == Clipboard::DRAG_BUFFER) {
  data_object = WebDropTarget::GetDataObject();
} else {
  ::OleGetClipboard(data_object.Receive());
}
ClipboardUtils::GetUrl(data_object, x, y);

etc.

[tony, 2010-07-02 03:49:34]

Mainly some style nits.

http://codereview.chromium.org/2842016/diff/8001/9001
File app/clipboard/clipboard.h (right):

http://codereview.chromium.org/2842016/diff/8001/9001#newcode86
app/clipboard/clipboard.h:86: static bool IsValidBuffer(int32 buffer) {
Nit: Does this method need to be updated to know about BUFFER_DRAG or renamed?

http://codereview.chromium.org/2842016/diff/8001/9002
File chrome/browser/clipboard_dispatcher.h (right):

http://codereview.chromium.org/2842016/diff/8001/9002#newcode14
chrome/browser/clipboard_dispatcher.h:14: // "Clipboard" is being used
I don't understand this comment.  Please make a class level comment explaining
how this class fits in with the other clipboard classes (i.e., why the methods
don't belong in Clipboard).

http://codereview.chromium.org/2842016/diff/8001/9002#newcode17
chrome/browser/clipboard_dispatcher.h:17: static std::vector<string16>
ReadAvailableTypes(Clipboard::Buffer buffer,
Nit: Maybe pass in a std::vector<string16>* instead of returning the vector of
string16 to avoid the copy?  Maybe all the Read methods in this class should
have a consistent return value (e.g., a bool that returns true on successful
read).

http://codereview.chromium.org/2842016/diff/8001/9002#newcode21
chrome/browser/clipboard_dispatcher.h:21: static std::vector<string16>
ReadFilenames(Clipboard::Buffer buffer);
same as above

[dcheng, 2010-07-03 00:18:02]

http://codereview.chromium.org/2842016/diff/8001/9001
File app/clipboard/clipboard.h (right):

http://codereview.chromium.org/2842016/diff/8001/9001#newcode86
app/clipboard/clipboard.h:86: static bool IsValidBuffer(int32 buffer) {
On 2010/07/02 03:49:34, tony wrote:
> Nit: Does this method need to be updated to know about BUFFER_DRAG or renamed?

Oops. Updated render_messages.h as well.

http://codereview.chromium.org/2842016/diff/8001/9002
File chrome/browser/clipboard_dispatcher.h (right):

http://codereview.chromium.org/2842016/diff/8001/9002#newcode14
chrome/browser/clipboard_dispatcher.h:14: // "Clipboard" is being used
On 2010/07/02 03:49:34, tony wrote:
> I don't understand this comment.  Please make a class level comment explaining
> how this class fits in with the other clipboard classes (i.e., why the methods
> don't belong in Clipboard).

Done.

http://codereview.chromium.org/2842016/diff/8001/9002#newcode17
chrome/browser/clipboard_dispatcher.h:17: static std::vector<string16>
ReadAvailableTypes(Clipboard::Buffer buffer,
On 2010/07/02 03:49:34, tony wrote:
> Nit: Maybe pass in a std::vector<string16>* instead of returning the vector of
> string16 to avoid the copy?  Maybe all the Read methods in this class should
> have a consistent return value (e.g., a bool that returns true on successful
> read).

Done. Not 100% sure the bool return value will be used, but might as well have
it there.

http://codereview.chromium.org/2842016/diff/8001/9002#newcode21
chrome/browser/clipboard_dispatcher.h:21: static std::vector<string16>
ReadFilenames(Clipboard::Buffer buffer);
On 2010/07/02 03:49:34, tony wrote:
> same as above

Done.

[tony, 2010-07-03 11:56:50]

LGTM

http://codereview.chromium.org/2842016/diff/8001/9002
File chrome/browser/clipboard_dispatcher.h (right):

http://codereview.chromium.org/2842016/diff/8001/9002#newcode17
chrome/browser/clipboard_dispatcher.h:17: static std::vector<string16>
ReadAvailableTypes(Clipboard::Buffer buffer,
On 2010/07/03 00:18:03, dcheng wrote:
> On 2010/07/02 03:49:34, tony wrote:
> > Nit: Maybe pass in a std::vector<string16>* instead of returning the vector
of
> > string16 to avoid the copy?  Maybe all the Read methods in this class should
> > have a consistent return value (e.g., a bool that returns true on successful
> > read).
> 
> Done. Not 100% sure the bool return value will be used, but might as well have
> it there.

Feel free to change to void functions if you don't think the return is ever
going to be used.

http://codereview.chromium.org/2842016/diff/36001/37018
File webkit/tools/test_shell/simple_clipboard_impl.cc (right):

http://codereview.chromium.org/2842016/diff/36001/37018#newcode55
webkit/tools/test_shell/simple_clipboard_impl.cc:55: std::vector<string16>
ClipboardReadAvailableTypes(Clipboard::Buffer buffer,
This needs to be updated too.