[tracing] Introduce "allowed_dump_modes" for memory dump config

base/trace_event/memory_dump_manager_unittest.cc

Index: base/trace_event/memory_dump_manager_unittest.cc
diff --git a/base/trace_event/memory_dump_manager_unittest.cc b/base/trace_event/memory_dump_manager_unittest.cc
index 6fa6624e1eb159a0da1010562226a10aacb73dab..73845b26f857c27dece9a60aa7cf0406eac80a86 100644
--- a/base/trace_event/memory_dump_manager_unittest.cc
+++ b/base/trace_event/memory_dump_manager_unittest.cc
@@ -1148,6 +1148,17 @@ TEST_F(MemoryDumpManagerTest, TestBackgroundTracingSetup) {
 
   EnableTracingWithTraceConfig(
       TraceConfigMemoryTestUtil::GetTraceConfig_BackgroundTrigger());
+
+  // Only background mode dumps should be allowed with the trace config.
+  last_callback_success_ = false;
+  RequestGlobalDumpAndWait(MemoryDumpType::EXPLICITLY_TRIGGERED,
+                           MemoryDumpLevelOfDetail::LIGHT);
+  EXPECT_FALSE(last_callback_success_);
+  last_callback_success_ = false;
+  RequestGlobalDumpAndWait(MemoryDumpType::EXPLICITLY_TRIGGERED,
+                           MemoryDumpLevelOfDetail::DETAILED);
+  EXPECT_FALSE(last_callback_success_);
+
   ASSERT_TRUE(IsPeriodicDumpingEnabled());
   run_loop.Run();
   DisableTracing();