DevTools: use diff_match_patch instead of jsdifflib for text diffing.

Source/devtools/BUILD.gn

 # Copyright 2014 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.
 
 import("//build/config/features.gni")
 
 gypi_values = exec_script(
     "//build/gypi_to_gn.py",
     [ rebase_path("devtools.gypi") ],
     "scope",
@@ skipping 21 matching lines @@
   gypi_values.devtools_extension_api_files
 
 devtools_modules_js_files =
   gypi_values.devtools_accessibility_js_files +
   gypi_values.devtools_audits_js_files +
   gypi_values.devtools_animation_js_files +
   gypi_values.devtools_cm_modes_js_files +
   gypi_values.devtools_components_lazy_js_files +
   gypi_values.devtools_console_js_files +
   gypi_values.devtools_devices_js_files +
+  gypi_values.devtools_diff_js_files +
   gypi_values.devtools_elements_js_files +
   gypi_values.devtools_emulated_devices_js_files +
   devtools_extensions_js_files +
   gypi_values.devtools_heap_snapshot_worker_js_files +
   gypi_values.devtools_layers_js_files +
   gypi_values.devtools_network_js_files +
   gypi_values.devtools_profiler_js_files +
   gypi_values.devtools_promises_js_files +
   gypi_values.devtools_resources_js_files +
   gypi_values.devtools_security_js_files +
@@ skipping 90 matching lines @@
       resources_out_dir + "inspector.js",
       resources_out_dir + "toolbox.css",
       resources_out_dir + "toolbox.html",
       resources_out_dir + "toolbox.js",
       resources_out_dir + "accessibility_module.js",
       resources_out_dir + "audits_module.js",
       resources_out_dir + "animation_module.js",
       resources_out_dir + "components_lazy_module.js",
       resources_out_dir + "console_module.js",
       resources_out_dir + "devices_module.js",
+      resources_out_dir + "diff_module.js",
       resources_out_dir + "elements_module.js",
       resources_out_dir + "heap_snapshot_worker_module.js",
       resources_out_dir + "layers_module.js",
       resources_out_dir + "network_module.js",
       resources_out_dir + "profiler_module.js",
       resources_out_dir + "promises_module.js",
       resources_out_dir + "resources_module.js",
       resources_out_dir + "security_module.js",
       resources_out_dir + "script_formatter_worker_module.js",
       resources_out_dir + "settings_module.js",
@@ skipping 94 matching lines @@
     outputs += [
       resources_out_dir + "inspector.js",
       resources_out_dir + "toolbox.js",
       resources_out_dir + "accessibility_module.js",
       resources_out_dir + "audits_module.js",
       resources_out_dir + "animation_module.js",
       resources_out_dir + "cm_modes_module.js",
       resources_out_dir + "components_lazy_module.js",
       resources_out_dir + "console_module.js",
       resources_out_dir + "devices_module.js",
+      resources_out_dir + "diff_module.js",
       resources_out_dir + "elements_module.js",
       resources_out_dir + "emulated_devices_module.js",
       resources_out_dir + "heap_snapshot_worker_module.js",
       resources_out_dir + "layers_module.js",
       resources_out_dir + "network_module.js",
       resources_out_dir + "profiler_module.js",
       resources_out_dir + "promises_module.js",
       resources_out_dir + "resources_module.js",
       resources_out_dir + "security_module.js",
       resources_out_dir + "screencast_module.js",
@@ skipping 66 matching lines @@
   }
 
   concatenate_css("concatenated_inspector_css") {
     app_name = "inspector"
   }
 
   concatenate_css("concatenated_toolbox_css") {
     app_name = "toolbox"
   }
 }