Send screenshots back to the client for debugging

chrome/test/webdriver/commands/response.cc

 // Copyright (c) 2011 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/test/webdriver/commands/response.h"
 
 #include "base/json/json_writer.h"
 #include "base/logging.h"
 #include "base/values.h"
 
@@ skipping 35 matching lines @@
   Value* out = NULL;
   LOG_IF(WARNING, !data_.Get(kValueKey, &out))
       << "Accessing unset response value.";  // Should never happen.
   return out;
 }
 
 void Response::SetValue(Value* value) {
   data_.Set(kValueKey, value);
 }
 
-void Response::SetError(ErrorCode error_code, const std::string& message,
-                        const std::string& file, int line) {
+void Response::SetError(ErrorCode error_code,
+                        const std::string& message,
+                        const std::string& file,
+                        int line,
+                        const std::string& screenshot) {
   DictionaryValue* error = new DictionaryValue;
   error->SetString(kMessageKey, message);
   error->SetString(kStackTraceFileNameKey, file);
   error->SetInteger(kStackTraceLineNumberKey, line);
 
+  if (!screenshot.empty()) {
+    error->SetString(kScreenKey, screenshot);
+  }
+
   SetStatus(error_code);
   SetValue(error);
 }
 
 void Response::SetField(const std::string& key, Value* value) {
   data_.Set(key, value);
 }
 
 std::string Response::ToJSON() const {
   std::string json;
   base::JSONWriter::Write(&data_, false, &json);
   return json;
 }
 
 }  // namespace webdriver