This CL adds client.toDataURL which gets the contents...

tests/build.scons

 # Copyright 2009, Google Inc.
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
@@ skipping 236 matching lines @@
     'import/cross/memory_buffer_test.cc',
     'import/cross/memory_stream_test.cc',
     'import/cross/raw_data_test.cc',
     'import/cross/tar_generator_test.cc',
     'import/cross/tar_processor_test.cc',
     'import/cross/targz_generator_test.cc',
     'import/cross/targz_processor_test.cc',
     'import/cross/threaded_stream_processor_test.cc',
     'serializer/cross/serializer_test.cc',
     'tests/common/cross/test_utils.cc',
+    'utils/cross/base64_test.cc',
+    'utils/cross/dataurl_test.cc',
     'utils/cross/file_path_utils_test.cc',
     'utils/cross/file_text_reader_test.cc',
     'utils/cross/json_writer_test.cc',
     'utils/cross/math_gtest.cc',
     'utils/cross/math_gtest_test.cc',
     'utils/cross/string_reader_test.cc',
     'utils/cross/string_writer_test.cc',
     'utils/cross/temporary_file_test.cc',
 ]
 
@@ skipping 511 matching lines @@
 # Adding extra line for cleaner formatting.
 env.Help('\n')
 
 
 #--------------------------------------------------------------------------
 # Other odds and ends
 
 # Install presubmit_tests batch file.
 # TODO: is this really needed anymore?
 env.Replicate('$ARTIFACTS_DIR', 'presubmit_tests.bat')