chore: fix path to dump_syms in the windows breakpad tool

appveyor.yml

@@ -37,6 +37,7 @@ build_script:
   - appveyor PushArtifact out/ffmpeg/ffmpeg.zip
   - ps: >-
       if ($env:GN_CONFIG -eq 'release') {
+        ninja -C out/Default third_party/breakpad:dump_syms
         python electron\script\dump-symbols.py -d %cd%/out/Default/electron.breakpad.syms
         python electron\script\zip-symbols.py
         appveyor PushArtifact out/Default/electron.breakpad.syms

tools/win/generate_breakpad_symbols.py

@@ -16,10 +16,20 @@ import subprocess
 import sys
 import threading
 
+GN_SRC_DIR = os.path.abspath(os.path.join(__file__, '..', '..', '..', '..'))
+
+# Duplicated as this script lives in tools not script
+def get_out_dir():
+  out_dir = 'Debug'
+  override = os.environ.get('ELECTRON_OUT_DIR')
+  if override is not None:
+    out_dir = override
+  return os.path.join(GN_SRC_DIR, 'out', out_dir)
+
 
 CONCURRENT_TASKS=4
-SOURCE_ROOT=os.path.abspath(os.path.dirname(os.path.dirname(os.path.dirname(__file__))))
-DUMP_SYMS=os.path.join(SOURCE_ROOT, 'vendor', 'breakpad', 'dump_syms.exe')
+OUT_DIR=get_out_dir()
+DUMP_SYMS=os.path.join(OUT_DIR, 'dump_syms.exe')
 
 
 def GetCommandOutput(command):