Always strip absolute paths from debug symbols.

If the build configurations supports stripping of absolute paths from debug
symbols by default, then it cannot be disabled. If it's causing problems, then
the user should file a bug.

This was prompted by this discussion thread:
https://groups.google.com/a/chromium.org/d/msg/chromium-dev/kE1HeGL4mj0/w_E5OCRLAwAJ

where a user disabled the configuration when the real problem was that they were
using Xcode 10.1, which had a bug that was fixed in Xcode 10.3.

Change-Id: I87598a84bf0c16d777114774656fc9b0b06999ed
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1898778
Commit-Queue: Erik Chen <erikchen@chromium.org>
Auto-Submit: Erik Chen <erikchen@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#719378}

build/config/compiler/compiler.gni

@@ -199,19 +199,29 @@ declare_args() {
                      current_cpu == "mipsel" || current_cpu == "mips64el")) ||
        (is_android && (current_cpu == "x86" || current_cpu == "x64" ||
                        current_cpu == "arm" || current_cpu == "arm64")))
+}
+
+# Use relative paths for debug info. This is important to make the build
+# results independent of the checkout and build directory names, which
+# in turn is important for goma compile hit rate.
+# Setting this to true may make it harder to debug binaries on Linux, see
+# https://chromium.googlesource.com/chromium/src/+/master/docs/linux_debugging.md#Source-level-debug-with-fdebug_compilation_dir
+# It's not clear if the crash server will correctly handle dSYMs with relative
+# paths, so we disable this feature for official benefit. The main benefit is
+# deterministic builds to reduce compile times, so this is less relevant for
+# official builders.
+strip_absolute_paths_from_debug_symbols_default =
+    is_android || is_fuchsia || is_nacl || (is_win && use_lld) || is_linux ||
+    (is_mac && !enable_dsyms)
 
-  # Use relative paths for debug info. This is important to make the build
-  # results independent of the checkout and build directory names, which
-  # in turn is important for goma compile hit rate.
-  # Setting this to true may make it harder to debug binaries on Linux, see
-  # https://chromium.googlesource.com/chromium/src/+/master/docs/linux_debugging.md#Source-level-debug-with-fdebug_compilation_dir
-  # It's not clear if the crash server will correctly handle dSYMs with relative
-  # paths, so we disable this feature for official benefit. The main benefit is
-  # deterministic builds to reduce compile times, so this is less relevant for
-  # official builders.
-  strip_absolute_paths_from_debug_symbols =
-      is_android || is_fuchsia || is_nacl || (is_win && use_lld) || is_linux ||
-      (is_mac && !enable_dsyms)
+# If the platform uses stripped absolute paths by default, then we don't expose
+# it as a configuration option. If this is causing problems, please file a bug.
+if (strip_absolute_paths_from_debug_symbols_default) {
+  strip_absolute_paths_from_debug_symbols = true
+} else {
+  declare_args() {
+    strip_absolute_paths_from_debug_symbols = false
+  }
 }
 
 # If it wasn't manually set, set to an appropriate default.

tools/mb/mb_config.pyl

@@ -2316,10 +2316,7 @@
     },
 
     'goma': {
-      # strip_absolute_paths_from_debug_symbols is on by default on Linux and
-      # Windows, but not elsewhere. Since it helps goma's cache, set this to
-      # help Android builds.
-      'gn_args': 'use_goma=true strip_absolute_paths_from_debug_symbols=true',
+      'gn_args': 'use_goma=true',
     },
 
     'gpu_fyi_tests': {