DevTools: use diff_match_patch instead of jsdifflib for text diffing.

Source/devtools/devtools.gyp

 #
 # Copyright (C) 2013 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 100 matching lines @@
                             '<(PRODUCT_DIR)/resources/inspector/inspector.js',
                             '<(PRODUCT_DIR)/resources/inspector/toolbox.css',
                             '<(PRODUCT_DIR)/resources/inspector/toolbox.html',
                             '<(PRODUCT_DIR)/resources/inspector/toolbox.js',
                             '<(PRODUCT_DIR)/resources/inspector/accessibility_module.js',
                             '<(PRODUCT_DIR)/resources/inspector/animation_module.js',
                             '<(PRODUCT_DIR)/resources/inspector/audits_module.js',
                             '<(PRODUCT_DIR)/resources/inspector/components_lazy_module.js',
                             '<(PRODUCT_DIR)/resources/inspector/console_module.js',
                             '<(PRODUCT_DIR)/resources/inspector/devices_module.js',
+                            '<(PRODUCT_DIR)/resources/inspector/diff_module.js',
                             '<(PRODUCT_DIR)/resources/inspector/elements_module.js',
                             '<(PRODUCT_DIR)/resources/inspector/heap_snapshot_worker_module.js',
                             '<(PRODUCT_DIR)/resources/inspector/layers_module.js',
                             '<(PRODUCT_DIR)/resources/inspector/network_module.js',
                             '<(PRODUCT_DIR)/resources/inspector/profiler_module.js',
                             '<(PRODUCT_DIR)/resources/inspector/promises_module.js',
                             '<(PRODUCT_DIR)/resources/inspector/resources_module.js',
                             '<(PRODUCT_DIR)/resources/inspector/security_module.js',
                             '<(PRODUCT_DIR)/resources/inspector/script_formatter_worker_module.js',
                             '<(PRODUCT_DIR)/resources/inspector/settings_module.js',
@@ skipping 144 matching lines @@
                             '<(_output_path)/inspector.js',
                             '<(_output_path)/toolbox.html',
                             '<(_output_path)/toolbox.js',
                             '<(_output_path)/accessibility_module.js',
                             '<(_output_path)/animation_module.js',
                             '<(_output_path)/audits_module.js',
                             '<(_output_path)/cm_modes_module.js',
                             '<(_output_path)/components_lazy_module.js',
                             '<(_output_path)/console_module.js',
                             '<(_output_path)/devices_module.js',
+                            '<(_output_path)/diff_module.js',
                             '<(_output_path)/elements_module.js',
                             '<(_output_path)/emulated_devices_module.js',
                             '<(_output_path)/heap_snapshot_worker_module.js',
                             '<(_output_path)/layers_module.js',
                             '<(_output_path)/network_module.js',
                             '<(_output_path)/profiler_module.js',
                             '<(_output_path)/promises_module.js',
                             '<(_output_path)/resources_module.js',
                             '<(_output_path)/security_module.js',
                             '<(_output_path)/screencast_module.js',
@@ skipping 80 matching lines @@
                         ],
                         'search_path': [ 'front_end' ],
                         'outputs': ['<(PRODUCT_DIR)/resources/inspector/toolbox.css'],
                         'action': ['python', '<@(_script_name)', '<@(_input_stylesheet)', '<@(_outputs)'],
                     }],
                 },
             ],
         }],
     ], # conditions
 }