Added code to disable 'paste' if nothing is present in clipboard to paste.

chrome/browser/renderer_context_menu/render_view_context_menu.cc

Index: chrome/browser/renderer_context_menu/render_view_context_menu.cc
diff --git a/chrome/browser/renderer_context_menu/render_view_context_menu.cc b/chrome/browser/renderer_context_menu/render_view_context_menu.cc
index 7d7207c41db64c03a951433bbebdc06d793eac99..732aa8c6db5d3a0a35208d8cc0c8e878caeb0bdb 100644
--- a/chrome/browser/renderer_context_menu/render_view_context_menu.cc
+++ b/chrome/browser/renderer_context_menu/render_view_context_menu.cc
@@ -1370,9 +1370,13 @@ bool RenderViewContextMenu::IsCommandIdEnabled(int id) const {
       return !!(params_.edit_flags & WebContextMenuData::CanCopy);
 
     case IDC_CONTENT_CONTEXT_PASTE:
-    case IDC_CONTENT_CONTEXT_PASTE_AND_MATCH_STYLE:
-      return !!(params_.edit_flags & WebContextMenuData::CanPaste);
-
+    case IDC_CONTENT_CONTEXT_PASTE_AND_MATCH_STYLE: {
+      std::vector<base::string16> types;
+      bool ignore;
+      ui::Clipboard::GetForCurrentThread()->ReadAvailableTypes(

[darin (slow to review), 2014/08/06 16:31:33]

This is potentially an expensive call, right? Should we worry about this janking
up the UI thread of the browser? Perhaps there is no other way to implement this
behavior though?

+          ui::CLIPBOARD_TYPE_COPY_PASTE, &types, &ignore);
+      return !types.empty();
+    }
     case IDC_CONTENT_CONTEXT_DELETE:
       return !!(params_.edit_flags & WebContextMenuData::CanDelete);