Remove DWARF3/arm special-cases.

- These special-cases were in place due to a bug in dump_syms.
- The bug in dump_syms was fixed in commit
https://chromium.googlesource.com/breakpad/breakpad/+/f32b83eb08e9ee158d3037b2114357187fd45a05

Change-Id: Ic39b1f8ca3cd7e513817f0ee364d72eb3e65adad
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2357610Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Commit-Queue: Nelson Billing <nbilling@google.com>
Cr-Commit-Position: refs/heads/master@{#798902}

build/config/compiler/BUILD.gn

@@ -2287,18 +2287,6 @@ config("symbols") {
       # version 7 also produces debug data that is incompatible with Breakpad
       # dump_syms, so this is still required (https://crbug.com/622406).
       cflags += [ "-fno-standalone-debug" ]
-    }
-    if (!use_debug_fission && current_cpu == "arm") {
-      # dump_syms has issues with dwarf4 on arm, https://crbug.com/744956
-      # TODO(thakis): Remove this again once dump_syms is fixed.
-      #
-      # debug fission needs DWARF DIEs to be emitted at version 4.
-      # Chrome OS emits Debug Frame in DWARF2's .debug_frame v1 to make breakpad
-      # happy [1].
-      # Unless Android needs debug fission, DWARF3 is the simplest solution.
-      #
-      # [1] crrev.com/a81d5ade0b043208e06ad71a38bcf9c348a1a52f
-      cflags += [ "-gdwarf-3" ]
     } else if (is_mac) {
       # clang defaults to DWARF2 on macOS unless mac_deployment_target is
       # at least 10.11.
@@ -2375,11 +2363,7 @@ config("minimal_symbols") {
     }
   } else {
     cflags = []
-    if (current_cpu == "arm") {
-      # dump_syms has issues with dwarf4 on arm, https://crbug.com/744956
-      # TODO(thakis): Remove this again once dump_syms is fixed.
-      cflags += [ "-gdwarf-3" ]
-    } else if (is_mac) {
+    if (is_mac) {
       # clang defaults to DWARF2 on macOS unless mac_deployment_target is
       # at least 10.11.
       # TODO(thakis): Remove this once mac_deployment_target is 10.11.