Make v8 inspector not crash

sky/engine/v8_inspector/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/ui.gni")
 import("//sky/engine/config.gni")
 
 visibility = ["//sky/*"]
 
 gen_dir = "$root_gen_dir/v8_inspector"
@@ skipping 42 matching lines @@
     "InspectorState.h",
     "InstrumentingAgents.h",
     "JSONParser.cpp",
     "JSONParser.h",
     "PageDebuggerAgent.cpp",
     "PageDebuggerAgent.h",
     "PageScriptDebugServer.cpp",
     "PageScriptDebugServer.h",
     "PromiseTracker.cpp",
     "PromiseTracker.h",
+    "read_from_source_tree.cc",
+    "read_from_source_tree.h",
     "ScriptBreakpoint.h",
     "ScriptDebugListener.h",
     "ScriptDebugServer.cpp",
     "ScriptDebugServer.h",
     "ScriptPreprocessor.cpp",
     "ScriptPreprocessor.h",
     "ScriptRegexp.cpp",
     "ScriptRegexp.h",
   ]
 
@@ skipping 39 matching lines @@
 
   inputs = [ protocol_file ]
   output_file = "$gen_dir/InspectorProtocolVersion.h"
   outputs = [ output_file ]
 
   args = [
     "-o", rebase_path(output_file, root_build_dir),
     rebase_path(protocol_file, root_build_dir),
   ]
 }