Bug 1598992 - Add test for profile hand-off from Base to Gecko Profiler - r=gregtatum

Differential Revision: https://phabricator.services.mozilla.com/D54446

--HG--
extra : moz-landing-system : lando

tools/profiler/tests/gtest/GeckoProfiler.cpp

@@ -1722,3 +1722,52 @@ TEST(GeckoProfiler, PostSamplingCallback)
   ASSERT_TRUE(!profiler_callback_after_sampling(
       [&](SamplingState) { ASSERT_TRUE(false); }));
 }
+
+#ifdef MOZ_BASE_PROFILER
+TEST(GeckoProfiler, BaseProfilerHandOff)
+{
+  const char* filters[] = {"GeckoMain"};
+
+  ASSERT_TRUE(!baseprofiler::profiler_is_active());
+  ASSERT_TRUE(!profiler_is_active());
+
+  // Start the Base Profiler.
+  baseprofiler::profiler_start(
+      PROFILER_DEFAULT_ENTRIES, PROFILER_DEFAULT_INTERVAL,
+      ProfilerFeature::StackWalk, filters, MOZ_ARRAY_LENGTH(filters));
+
+  ASSERT_TRUE(baseprofiler::profiler_is_active());
+  ASSERT_TRUE(!profiler_is_active());
+
+  // Add at least a marker, which should go straight into the buffer.
+  Maybe<baseprofiler::ProfilerBufferInfo> info0 =
+      baseprofiler::profiler_get_buffer_info();
+  BASE_PROFILER_ADD_MARKER("Marker from base profiler", OTHER);
+  Maybe<baseprofiler::ProfilerBufferInfo> info1 =
+      baseprofiler::profiler_get_buffer_info();
+  ASSERT_GT(info1->mRangeEnd, info0->mRangeEnd);
+
+  // Start the Gecko Profiler, which should grab the Base Profiler profile and
+  // stop it.
+  profiler_start(PROFILER_DEFAULT_ENTRIES, PROFILER_DEFAULT_INTERVAL,
+                 ProfilerFeature::StackWalk, filters,
+                 MOZ_ARRAY_LENGTH(filters));
+
+  ASSERT_TRUE(!baseprofiler::profiler_is_active());
+  ASSERT_TRUE(profiler_is_active());
+
+  // Write some Gecko Profiler samples.
+  ASSERT_EQ(WaitForSamplingState(), SamplingState::SamplingCompleted);
+
+  // Check that the Gecko Profiler profile contains at least the Base Profiler
+  // main thread samples.
+  UniquePtr<char[]> profile = profiler_get_profile();
+  ASSERT_TRUE(profile);
+  ASSERT_TRUE(profile[0] == '{');
+  ASSERT_TRUE(strstr(profile.get(), "GeckoMain (pre-xul)"));
+  ASSERT_TRUE(strstr(profile.get(), "Marker from base profiler"));
+
+  profiler_stop();
+  ASSERT_TRUE(!profiler_is_active());
+}
+#endif  // MOZ_BASE_PROFILER