[CfT] Enable console crash stack trace in Chrome for Testing

Official Chrome builds do not dump crash stack trace to console due to
security concerns. However, Chrome for Testing does not report crashes
via BreakPad/CrashPad like regular Chrome, so CfT crashes are silent.

Since security expectations for Chrome for Testing are much lower than
that of the regular Chrome, we can safely enable console crash stack
trace in official CfT builds.

Bug: 391306181
Change-Id: I7977ee55d9be4f3bec346dad24e70f0cbc31f61f
Cq-Include-Trybots: luci.chromium.try:linux-rel-cft,win-rel-cft
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6403433
Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Commit-Queue: Peter Kvitek <kvitekp@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1439369}

content/app/content_main_runner_impl.cc

@@ -52,6 +52,7 @@
 #include "base/threading/platform_thread.h"
 #include "base/time/time.h"
 #include "base/trace_event/trace_event.h"
+#include "build/branding_buildflags.h"
 #include "build/build_config.h"
 #include "components/discardable_memory/service/discardable_shared_memory_manager.h"
 #include "components/download/public/common/download_task_runner.h"
@@ -991,7 +992,7 @@ int ContentMainRunnerImpl::Initialize(ContentMainParams params) {
         return nullptr;
       }));
 
-#if !defined(OFFICIAL_BUILD)
+#if !defined(OFFICIAL_BUILD) || BUILDFLAG(CHROME_FOR_TESTING)
 #if BUILDFLAG(IS_WIN)
   bool should_enable_stack_dump = !process_type.empty();
 #else
@@ -1008,7 +1009,7 @@ int ContentMainRunnerImpl::Initialize(ContentMainParams params) {
   }
 
   base::debug::VerifyDebugger();
-#endif  // !defined(OFFICIAL_BUILD)
+#endif  // !defined(OFFICIAL_BUILD) || BUILDFLAG(CHROME_FOR_TESTING)
 
   delegate_->PreSandboxStartup();