Reapply "[vm] Don't enable the profiler by default. Enable the profiler at startup with --observe, …

runtime/vm/service.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/service.h"
 
 #include "include/dart_api.h"
 #include "include/dart_native_api.h"
 #include "platform/globals.h"
 
@@ skipping 11 matching lines @@
 #include "vm/message_handler.h"
 #include "vm/native_arguments.h"
 #include "vm/native_entry.h"
 #include "vm/native_symbol.h"
 #include "vm/object.h"
 #include "vm/object_graph.h"
 #include "vm/object_id_ring.h"
 #include "vm/object_store.h"
 #include "vm/parser.h"
 #include "vm/port.h"
+#include "vm/profiler.h"
 #include "vm/profiler_service.h"
 #include "vm/reusable_handles.h"
 #include "vm/safepoint.h"
 #include "vm/service_event.h"
 #include "vm/service_isolate.h"
 #include "vm/source_report.h"
 #include "vm/stack_frame.h"
 #include "vm/symbols.h"
 #include "vm/timeline.h"
 #include "vm/type_table.h"
@@ skipping 3072 matching lines @@
   // the service isolate directly, but would require some special case
   // code.  That would prevent this isolate getting double-interrupted
   // with OOB messages.
   Isolate* isolate = thread->isolate();
   isolate->SendInternalLibMessage(Isolate::kInterruptMsg,
                                   isolate->pause_capability());
   PrintSuccess(js);
   return true;
 }
 
+static const MethodParameter* enable_profiler_params[] = {
+    NULL,
+};
+
+static bool EnableProfiler(Thread* thread, JSONStream* js) {
+  if (!FLAG_profiler) {
+    FLAG_profiler = true;
+    Profiler::InitOnce();
+  }
+  PrintSuccess(js);
+  return true;
+}
+
 static const MethodParameter* get_tag_profile_params[] = {
     RUNNABLE_ISOLATE_PARAMETER, NULL,
 };
 
 static bool GetTagProfile(Thread* thread, JSONStream* js) {
   JSONObject miniProfile(js);
   miniProfile.AddProperty("type", "TagProfile");
   thread->isolate()->vm_tag_counters()->PrintToJSONObject(&miniProfile);
   return true;
 }
@@ skipping 881 matching lines @@
   { "addBreakpointWithScriptUri", AddBreakpointWithScriptUri,
     add_breakpoint_with_script_uri_params },
   { "addBreakpointAtEntry", AddBreakpointAtEntry,
     add_breakpoint_at_entry_params },
   { "_addBreakpointAtActivation", AddBreakpointAtActivation,
     add_breakpoint_at_activation_params },
   { "_clearCpuProfile", ClearCpuProfile,
     clear_cpu_profile_params },
   { "_clearVMTimeline", ClearVMTimeline,
     clear_vm_timeline_params, },
+  { "_enableProfiler", EnableProfiler,
+    enable_profiler_params, },
   { "evaluate", Evaluate,
     evaluate_params },
   { "evaluateInFrame", EvaluateInFrame,
     evaluate_in_frame_params },
   { "_getAllocationProfile", GetAllocationProfile,
     get_allocation_profile_params },
   { "_getAllocationSamples", GetAllocationSamples,
       get_allocation_samples_params },
   { "_getNativeAllocationSamples", GetNativeAllocationSamples,
       get_native_allocation_samples_params },
@@ skipping 91 matching lines @@
     if (strcmp(method_name, method.name) == 0) {
       return &method;
     }
   }
   return NULL;
 }
 
 #endif  // !PRODUCT
 
 }  // namespace dart