Send screenshots back to the client for debugging

chrome/test/webdriver/commands/response.h

-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// 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.
 
 #ifndef CHROME_TEST_WEBDRIVER_COMMANDS_RESPONSE_H_
 #define CHROME_TEST_WEBDRIVER_COMMANDS_RESPONSE_H_
 
 #include <sstream>
 #include <string>
 
 #include "base/values.h"
 #include "chrome/test/webdriver/error_codes.h"
 
 namespace webdriver {
 
 // All errors in webdriver must use this macro in order to send back
-// a proper stack trace to the client
+// a proper stack trace to the client.
 #define SET_WEBDRIVER_ERROR(response, msg, err) \
   response->SetError(err, msg, __FILE__, __LINE__); \
   LOG(ERROR) << msg
 
+// Error which need to send back a screenshot should use this macro.
+// |png| needs to be a string which contains the raw binary data of
+// the PNG file.
+#define SET_WEBDRIVER_ERROR_WITH_SCREENSHOT(response, msg, err , png) \
+  response->SetError(err, msg, __FILE__, __LINE__, png); \
+  LOG(ERROR) << msg
+
 // A simple class that encapsulates the information describing the response to
 // a |Command|. In Webdriver all responses must be sent back as a JSON value,
 // conforming to the spec found at:
 // http://code.google.com/p/selenium/wiki/JsonWireProtocol#Messages
 class Response {
  public:
   // Creates a new |Response| with a default status of |kSuccess| and a
   // |NullValue|.
   Response();
   ~Response();
 
   ErrorCode GetStatus() const;
   void SetStatus(ErrorCode status);
 
   // Ownership of the returned pointer is kept by this object.
   const Value* GetValue() const;
 
   // Sets the |value| of this response, assuming ownership of the object in the
   // process.
   void SetValue(Value* value);
 
   // Configures this response to report an error. The |file| and |line|
   // parameters, which identify where in the source the error occurred, can be
   // set using the |SET_WEBDRIVER_ERROR| macro above.
   void SetError(ErrorCode error, const std::string& message,
                 const std::string& file, int line);
 
+  // Configures this response to report an error. The |file| and |line|
+  // parameters, which identify where in the source the error occurred, can be
+  // set using the |SET_WEBDRIVER_ERROR_WITH_SCREENSHOT| macro above.  Includes
+  // a screen shot of the tab which caused the error.
+  void SetError(ErrorCode error,
+                const std::string& message,
+                const std::string& file,
+                int line,
+                const std::string& png);
+
   // Sets a JSON field in this response. The |key| may be a "." delimitted
   // string to indicate the value should be set in a nested object. Any
   // previously set value for the |key| will be deleted.
   // This object assumes ownership of |value|.
   void SetField(const std::string& key, Value* value);
 
   // Returns this response as a JSON string.
   std::string ToJSON() const;
 
  private:
   DictionaryValue data_;
 
   DISALLOW_COPY_AND_ASSIGN(Response);
 };
 
 }  // namespace webdriver
 
 #endif  // CHROME_TEST_WEBDRIVER_COMMANDS_RESPONSE_H_