Fix the HTML5 drag and drop demos on Linux and CrOS

chrome/browser/ui/views/omnibox/omnibox_view_views.cc

 // 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.
 
 #include "chrome/browser/ui/views/omnibox/omnibox_view_views.h"
 
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 #include "base/strings/string_util.h"
@@ skipping 919 matching lines @@
   }
 }
 
 void OmniboxViewViews::OnWriteDragData(ui::OSExchangeData* data) {
   GURL url;
   bool write_url;
   bool is_all_selected = IsSelectAll();
   base::string16 selected_text = GetSelectedText();
   model()->AdjustTextForCopy(GetSelectedRange().GetMin(), is_all_selected,
                              &selected_text, &url, &write_url);
-  data->SetString(selected_text);
   if (write_url) {
     gfx::Image favicon;
     base::string16 title = selected_text;
     if (is_all_selected)
       model()->GetDataForURLExport(&url, &title, &favicon);
     button_drag_utils::SetURLAndDragImage(url, title, favicon.AsImageSkia(),
                                           NULL, data, GetWidget());
     data->SetURL(url, title);
+  } else {
+    data->SetString(selected_text);

[sky, 2014/07/09 20:39:08]

Why don't we always want to set the string content?

[pkotwicz, 2014/07/09 23:00:18]

The string content is set by the first caller of OSExchangeData::SetString().

If we want the string content to be set by OSExchangeData::SetURL() on Windows
(as it is on CrOS and Linux without this CL), OSExchangeData::SetURL() must be
called before OSExchangeData::SetString()

OSExchangeData::SetURL() calls OSExchangeData::SetString() internally

The string being set by the first call to OSExchangeData::SetString() is weird.
However, on Windows, data is set on OSExchangeData in the order of highest to
lowest priority. If OSExchangeData::SetString() were to overwrite the currently
set string, it is unclear whether the priority would also change. The
requirement to prioritize data formats seems to be driven by IEnumFORMATETC

[sky, 2014/07/10 16:13:03]

Was this always the case? I wonder if SetURL should not touch the string data.

   }
 }
 
 void OmniboxViewViews::OnGetDragOperationsForTextfield(int* drag_operations) {
   base::string16 selected_text = GetSelectedText();
   GURL url;
   bool write_url;
   model()->AdjustTextForCopy(GetSelectedRange().GetMin(), IsSelectAll(),
                              &selected_text, &url, &write_url);
   if (write_url)
@@ skipping 50 matching lines @@
     menu_contents->InsertItemWithStringIdAt(
         select_all_position + 1, IDS_SHOW_URL, IDS_SHOW_URL);
   }
 
   // Minor note: We use IDC_ for command id here while the underlying textfield
   // is using IDS_ for all its command ids. This is because views cannot depend
   // on IDC_ for now.
   menu_contents->AddItemWithStringId(IDC_EDIT_SEARCH_ENGINES,
       IDS_EDIT_SEARCH_ENGINES);
 }