Implement the WebSmartPaste pasteboard type on Mac, stub it out on Linux, rem...

base/clipboard_mac.mm

Index: base/clipboard_mac.mm
===================================================================
--- base/clipboard_mac.mm	(revision 5474)
+++ base/clipboard_mac.mm	(working copy)
@@ -15,6 +15,10 @@
 // Would be nice if this were in UTCoreTypes.h, but it isn't
 const NSString* kUTTypeURLName = @"public.url-name";
 
+// Tells us if WebKit was the last to write to the pasteboard. There's no
+// actual data associated with this type.
+const NSString *kWebSmartPastePboardType = @"NeXT smart paste pasteboard type";
+
 NSPasteboard* GetPasteboard() {
   // The pasteboard should not be nil in a UI session, but this handy DCHECK
   // can help track down problems if someone tries using clipboard code outside
@@ -121,6 +125,14 @@
   [pb setPropertyList:fileList forType:NSFilenamesPboardType];
 }
 
+// Write an extra flavor that signifies WebKit was the last to modify the
+// pasteboard. This flavor has no data.
+void Clipboard::WriteWebSmartPaste() {
+  NSPasteboard* pb = GetPasteboard();
+  [pb addTypes:[NSArray arrayWithObject:NSStringPboardType] owner:nil];
+  [pb setData:nil forType:GetWebKitSmartPasteFormatType()];
+}
+
 bool Clipboard::IsFormatAvailable(NSString* format) const {
   NSPasteboard* pb = GetPasteboard();
   NSArray* types = [pb types];
@@ -250,3 +262,8 @@
 Clipboard::FormatType Clipboard::GetHtmlFormatType() {
   return NSHTMLPboardType;
 }
+
+// static
+Clipboard::FormatType Clipboard::GetWebKitSmartPasteFormatType() {
+  return kWebSmartPastePboardType;
+}