fix isInChromiumDirectory

Checkout of chromium directory may not have 'chromium'.
e.g.
https://ci.chromium.org/p/devtools-frontend/builders/try/devtools_frontend_linux_blink_light_rel
has chromium checkout under 'builder' dir.

Bug: 1278663
Change-Id: Icaef7e58ba93e30528ae23d352842abd3d0f3055
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/3414935
Auto-Submit: Takuto Ikuta <tikuta@chromium.org>
Reviewed-by: Tim Van der Lippe <tvanderlippe@chromium.org>
Commit-Queue: Tim Van der Lippe <tvanderlippe@chromium.org>
diff --git a/scripts/devtools_paths.js b/scripts/devtools_paths.js
index 81148a8..82ceca6 100644
--- a/scripts/devtools_paths.js
+++ b/scripts/devtools_paths.js
@@ -59,8 +59,9 @@
   }
 
   const normalizedPath = PATH_TO_EXECUTED_FILE.split(path.sep).join('/');
-  const isInChromium = normalizedPath.includes('chromium/src/third_party/devtools-frontend');
-  const potentialChromiumDir = PATH_TO_EXECUTED_FILE.substring(0, PATH_TO_EXECUTED_FILE.indexOf('chromium') + 8);
+  const devtoolsPath = 'src/third_party/devtools-frontend';
+  const isInChromium = normalizedPath.includes(devtoolsPath);
+  const potentialChromiumDir = PATH_TO_EXECUTED_FILE.substring(0, PATH_TO_EXECUTED_FILE.indexOf(devtoolsPath));
   const result = {isInChromium, chromiumDirectory: potentialChromiumDir};
   _lookUpCaches.set('chromium', result);
   return result;