Teach Google Test how to emit stack traces.

This CL provides an OsStackTraceGetterInterface implementation for
Google Test that uses Chromium's base::debug. This allows Google Test to
emit stack traces to make debugging test failures a bit easier. As a
result, failures that once looked like the following will now include
stack traces:

[ RUN      ] UpgradeDetectorImplTest.TestPeriodChanges
unknown file: error: Uninteresting mock function call - returning directly.
    Function call: OnUpgradeRecommended()
[  FAILED  ] UpgradeDetectorImplTest.TestPeriodChanges (3 ms)

BUG=none
R=dpranke@chromium.org

Change-Id: I992d807cc654104d0bad461fda8cb82c86e6e9f8
Reviewed-on: https://chromium-review.googlesource.com/1009947
Commit-Queue: Greg Thompson <grt@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#551083}

third_party/googletest/BUILD.gn

@@ -23,7 +23,10 @@ config("gtest_config") {
   ]
 
   # Gtest headers need to be able to find themselves.
-  include_dirs = [ "src/googletest/include" ]
+  include_dirs = [
+    "custom",
+    "src/googletest/include",
+  ]
 
   if (is_win) {
     cflags = [ "/wd4800" ]  # Unused variable warning.
@@ -43,6 +46,9 @@ config("gmock_config") {
 source_set("gtest") {
   testonly = true
   sources = [
+    "custom/gtest/internal/custom/gtest.h",
+    "custom/gtest/internal/custom/stack_trace_getter.cc",
+    "custom/gtest/internal/custom/stack_trace_getter.h",
     "src/googletest/include/gtest/gtest-death-test.h",
     "src/googletest/include/gtest/gtest-message.h",
     "src/googletest/include/gtest/gtest-param-test.h",
@@ -81,6 +87,17 @@ source_set("gtest") {
 
   configs -= [ "//build/config/compiler:chromium_code" ]
   configs += [ "//build/config/compiler:no_chromium_code" ]
+
+  if (is_nacl) {
+    sources -= [
+      "custom/gtest/internal/custom/stack_trace_getter.cc",
+      "custom/gtest/internal/custom/stack_trace_getter.h",
+    ]
+  } else {
+    deps = [
+      "//base",
+    ]
+  }
 }
 
 # Do NOT depend on this directly. Use //testing/gtest:gtest_main instead.

third_party/googletest/custom/gtest/internal/custom/DEPS

+# This directory contains Google Test glue that depends on //base.
+include_rules = [
+  '+base',
+  '+build',
+]

third_party/googletest/custom/gtest/internal/custom/gtest.h

+// Copyright 2018 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef THIRD_PARTY_GOOGLETEST_CUSTOM_GTEST_INTERNAL_CUSTOM_GTEST_H_
+#define THIRD_PARTY_GOOGLETEST_CUSTOM_GTEST_INTERNAL_CUSTOM_GTEST_H_
+
+#include "build/build_config.h"
+
+#if !defined(OS_NACL)
+#include "third_party/googletest/custom/gtest/internal/custom/stack_trace_getter.h"
+
+// Tell Google Test to use a stack trace getter based on Chromium's
+// base::debug::StackTrace.
+#define GTEST_OS_STACK_TRACE_GETTER_ StackTraceGetter
+#endif  // defined(OS_NACL)
+
+#endif  // THIRD_PARTY_GOOGLETEST_CUSTOM_GTEST_INTERNAL_CUSTOM_GTEST_H_

third_party/googletest/custom/gtest/internal/custom/stack_trace_getter.cc

+// Copyright 2018 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "third_party/googletest/custom/gtest/internal/custom/stack_trace_getter.h"
+
+#include "base/debug/stack_trace.h"
+#include "base/format_macros.h"
+
+namespace {
+
+// The number of frames on the top of the stack to ignore in UponLeavingGTest.
+// This may vary from build to build and platform to platform. On Windows
+// release builds at the time of writing, the top two frames should be skipped:
+//   base::debug::StackTrace::StackTrace
+//   StackTraceGetter::UponLeavingGTest
+enum : size_t { kDepartureSkipFrames = 2 };
+
+}  // namespace
+
+std::string StackTraceGetter::CurrentStackTrace(int max_depth, int skip_count) {
+  base::debug::StackTrace stack_trace;
+
+  size_t frame_count = 0;
+  const void* const* addresses = stack_trace.Addresses(&frame_count);
+
+  // Drop the frames at the tail that were present the last time gtest was left.
+  if (frame_count_upon_leaving_gtest_ &&
+      frame_count > frame_count_upon_leaving_gtest_) {
+    frame_count -= frame_count_upon_leaving_gtest_;
+  }
+
+  // Ignore frames to skip.
+  if (skip_count >= 0 && static_cast<size_t>(skip_count) < frame_count) {
+    frame_count -= skip_count;
+    addresses += skip_count;
+  }
+
+  // Only return as many as requested.
+  if (max_depth >= 0 && static_cast<size_t>(max_depth) < frame_count)
+    frame_count = static_cast<size_t>(max_depth);
+
+  return base::debug::StackTrace(addresses, frame_count).ToString();
+}
+
+void StackTraceGetter::UponLeavingGTest() {
+  // Remember how deep the stack is as gtest is left.
+  base::debug::StackTrace().Addresses(&frame_count_upon_leaving_gtest_);
+  if (frame_count_upon_leaving_gtest_ > kDepartureSkipFrames)
+    frame_count_upon_leaving_gtest_ -= kDepartureSkipFrames;
+}

third_party/googletest/custom/gtest/internal/custom/stack_trace_getter.h

+// Copyright 2018 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef THIRD_PARTY_GOOGLETEST_CUSTOM_GTEST_INTERNAL_CUSTOM_STACK_TRACE_GETTER_H_
+#define THIRD_PARTY_GOOGLETEST_CUSTOM_GTEST_INTERNAL_CUSTOM_STACK_TRACE_GETTER_H_
+
+#include <stddef.h>
+
+#include "third_party/googletest/src/googletest/src/gtest-internal-inl.h"
+
+// An implementation of Google Test's OsStackTraceGetterInterface that uses
+// Chromium's base::debug::StackTrace to obtain stringified stack traces.
+class StackTraceGetter
+    : public ::testing::internal::OsStackTraceGetterInterface {
+ public:
+  StackTraceGetter() = default;
+  ~StackTraceGetter() override = default;
+  StackTraceGetter(const StackTraceGetter&) = delete;
+  StackTraceGetter& operator=(const StackTraceGetter&) = delete;
+
+  // ::testing::internal::OsStackTraceGetterInterface:
+  std::string CurrentStackTrace(int max_depth, int skip_count) override;
+  void UponLeavingGTest() override;
+
+ private:
+  size_t frame_count_upon_leaving_gtest_ = 0;
+};
+
+#endif  // THIRD_PARTY_GOOGLETEST_CUSTOM_GTEST_INTERNAL_CUSTOM_STACK_TRACE_GETTER_H_