Pull in gmock through DEPS

testing/gmock/scripts/generator/README

-
-The Google Mock class generator is an application that is part of cppclean.
-For more information about cppclean, see the README.cppclean file or
-visit http://code.google.com/p/cppclean/
-
-cppclean requires Python 2.3.5 or later.  If you don't have Python installed
-on your system, you will also need to install it.  You can download Python
-from:  http://www.python.org/download/releases/
-
-To use the Google Mock class generator, you need to call it
-on the command line passing the header file and class for which you want
-to generate a Google Mock class.
-
-Make sure to install the scripts somewhere in your path.  Then you can
-run the program.
-
-  gmock_gen.py header-file.h [ClassName]...
-
-If no ClassNames are specified, all classes in the file are emitted.
-
-To change the indentation from the default of 2, set INDENT in
-the environment.  For example to use an indent of 4 spaces:
-
-INDENT=4 gmock_gen.py header-file.h ClassName
-
-This version was made from SVN revision 281 in the cppclean repository.
-
-Known Limitations
------------------
-Not all code will be generated properly.  For example, when mocking templated
-classes, the template information is lost.  You will need to add the template
-information manually.
-
-Not all permutations of using multiple pointers/references will be rendered
-properly.  These will also have to be fixed manually.