stack.py: Don't assume --chrome-symbols-dir values are relative to DIR_SORUCE_ROOT

This tripped me up. It's much less surprising to interpret relative
paths as being relative to CWD.

I could find no checked-in usages of this flag, so hopefully does not
break anything.

Change-Id: I6b6db76f2583027e5bc3eba15f49dd32b1b37bf3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3370067
Auto-Submit: Andrew Grieve <agrieve@chromium.org>
Reviewed-by: Siddhartha S <ssid@chromium.org>
Commit-Queue: Siddhartha S <ssid@chromium.org>
Cr-Commit-Position: refs/heads/main@{#956653}
NOKEYCHECK=True
GitOrigin-RevId: c7ff2988bf93f1ec508ec103d2d53a96e194ef34
diff --git a/development/scripts/stack.py b/development/scripts/stack.py
index bcd1685..6420406 100755
--- a/development/scripts/stack.py
+++ b/development/scripts/stack.py
@@ -50,12 +50,11 @@
   print("  usage: " + sys.argv[0] + " [options] [FILE]")
   print()
   print("  --symbols-dir=path")
-  print("       the path to a symbols dir, such as")
+  print("       path to the Android OS symbols dir, such as")
   print("       =/tmp/out/target/product/dream/symbols")
   print()
   print("  --chrome-symbols-dir=path")
-  print("       the path to a Chrome symbols dir (can be absolute or relative")
-  print("       to src), such as =out/Debug/lib.unstripped")
+  print("       path to a Chrome symbols dir. E.g.: out/Debug/lib.unstripped")
   print()
   print("  --output-directory=path")
   print("       the path to the build output directory, such as out/Debug.")
@@ -169,8 +168,7 @@
       symbol.ARCH = value
       arch_defined = True
     elif option == "--chrome-symbols-dir":
-      symbol.CHROME_SYMBOLS_DIR = os.path.join(constants.DIR_SOURCE_ROOT,
-                                               value)
+      symbol.CHROME_SYMBOLS_DIR = value
     elif option == "--output-directory":
       constants.SetOutputDirectory(os.path.abspath(value))
     elif option == "--apks-directory":