Remove superfluous INFO logs from //flutter/runtime. (#16280)

These add no value to engine developers anymore and are not visible to external
users because of the low log severity.

runtime/dart_isolate.cc

@@ -508,7 +508,6 @@ bool DartIsolate::Run(const std::string& entrypoint_name,
   }
 
   phase_ = Phase::Running;
-  FML_DLOG(INFO) << "New isolate is in the running state.";
 
   if (on_run) {
     on_run();
@@ -540,7 +539,6 @@ bool DartIsolate::RunFromLibrary(const std::string& library_name,
   }
 
   phase_ = Phase::Running;
-  FML_DLOG(INFO) << "New isolate is in the running state.";
 
   if (on_run) {
     on_run();
@@ -588,7 +586,6 @@ Dart_Isolate DartIsolate::DartCreateAndStartServiceIsolate(
   const auto& settings = vm_data->GetSettings();
 
   if (!settings.enable_observatory) {
-    FML_DLOG(INFO) << "Observatory is disabled.";
     return nullptr;
   }
 
@@ -834,9 +831,6 @@ void DartIsolate::DartIsolateShutdownCallback(
     std::shared_ptr<DartIsolateGroupData>* isolate_group_data,
     std::shared_ptr<DartIsolate>* isolate_data) {
   TRACE_EVENT0("flutter", "DartIsolate::DartIsolateShutdownCallback");
-  FML_DLOG(INFO) << "DartIsolateShutdownCallback"
-                 << " isolate_group_data " << isolate_group_data
-                 << " isolate_data " << isolate_data;
   isolate_data->get()->OnShutdownCallback();
 }
 
@@ -844,9 +838,6 @@ void DartIsolate::DartIsolateShutdownCallback(
 void DartIsolate::DartIsolateGroupCleanupCallback(
     std::shared_ptr<DartIsolateGroupData>* isolate_data) {
   TRACE_EVENT0("flutter", "DartIsolate::DartIsolateGroupCleanupCallback");
-  FML_DLOG(INFO) << "DartIsolateGroupCleanupCallback isolate_data "
-                 << isolate_data;
-
   delete isolate_data;
 }
 
@@ -855,9 +846,6 @@ void DartIsolate::DartIsolateCleanupCallback(
     std::shared_ptr<DartIsolateGroupData>* isolate_group_data,
     std::shared_ptr<DartIsolate>* isolate_data) {
   TRACE_EVENT0("flutter", "DartIsolate::DartIsolateCleanupCallback");
-
-  FML_DLOG(INFO) << "DartIsolateCleanupCallback cleaned up isolate_data "
-                 << isolate_data;
   delete isolate_data;
 }
 

runtime/dart_isolate_unittests.cc

@@ -111,7 +111,6 @@ class AutoIsolateShutdown {
     fml::AutoResetWaitableEvent latch;
     fml::TaskRunner::RunNowOrPostTask(
         runner_, [isolate = std::move(isolate_), &latch]() {
-          FML_LOG(INFO) << "Shutting down isolate.";
           if (!isolate->Shutdown()) {
             FML_LOG(ERROR) << "Could not shutdown isolate.";
             FML_CHECK(false);

runtime/dart_vm.cc

@@ -282,9 +282,6 @@ DartVM::DartVM(std::shared_ptr<const DartVMData> vm_data,
   FML_DCHECK(isolate_name_server_);
   FML_DCHECK(service_protocol_);
 
-  FML_DLOG(INFO) << "Attempting Dart VM launch for mode: "
-                 << (IsRunningPrecompiledCode() ? "AOT" : "Interpreter");
-
   {
     TRACE_EVENT0("flutter", "dart::bin::BootstrapDartIo");
     dart::bin::BootstrapDartIo();
@@ -456,9 +453,6 @@ DartVM::DartVM(std::shared_ptr<const DartVMData> vm_data,
     Dart_SetDartLibrarySourcesKernel(dart_library_sources->GetMapping(),
                                      dart_library_sources->GetSize());
   }
-
-  FML_DLOG(INFO) << "New Dart VM instance created. Instance count: "
-                 << gVMLaunchCount;
 }
 
 DartVM::~DartVM() {
@@ -478,9 +472,6 @@ DartVM::~DartVM() {
       << "Could not cleanly shut down the Dart VM. Error: \"" << result
       << "\".";
   free(result);
-
-  FML_DLOG(INFO) << "Dart VM instance destroyed. Instance count: "
-                 << gVMLaunchCount;
 }
 
 std::shared_ptr<const DartVMData> DartVM::GetVMData() const {