Add Generic Implementation of ClipboardRecentContent

ui/base/test/test_clipboard.cc

Index: ui/base/test/test_clipboard.cc
diff --git a/ui/base/test/test_clipboard.cc b/ui/base/test/test_clipboard.cc
index 2b1d483275550e5b46d4a8a60431e0fe0da6d0a1..7bceec164e97425f90bead0e72c2fd4064ade8c5 100644
--- a/ui/base/test/test_clipboard.cc
+++ b/ui/base/test/test_clipboard.cc
@@ -26,6 +26,10 @@ Clipboard* TestClipboard::CreateForCurrentThread() {
   return clipboard;
 }
 
+void TestClipboard::SetClipboardLastModifiedTime(const base::Time& time) {
+  last_modified_time_ = time;
+}
+
 void TestClipboard::OnPreShutdown() {}
 
 uint64_t TestClipboard::GetSequenceNumber(ClipboardType type) const {
@@ -126,6 +130,10 @@ void TestClipboard::ReadData(const FormatType& format,
     *result = it->second;
 }
 
+base::Time TestClipboard::GetClipboardLastModifiedTime() const {
+  return last_modified_time_;
+}
+
 void TestClipboard::WriteObjects(ClipboardType type, const ObjectMap& objects) {
   Clear(type);
   default_store_type_ = type;