Remove last reference to //base from //flutter/shell/platform/linux. (#3511)

shell/platform/linux/BUILD.gn

@@ -10,11 +10,10 @@ executable("linux") {
   ]
 
   deps = [
-    "//base",
     "//dart/runtime/bin:embedded_dart_io",
     "//flutter/common",
+    "//flutter/fml",
     "//flutter/shell/common",
-    "//flutter/shell/gpu",
     "//flutter/shell/testing",
     "//lib/ftl",
     "//lib/tonic",

shell/platform/linux/main_linux.cc

@@ -2,12 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "base/at_exit.h"
-#include "base/basictypes.h"
-#include "base/bind.h"
-#include "base/message_loop/message_loop.h"
 #include "dart/runtime/bin/embedded_dart_io.h"
 #include "flutter/common/threads.h"
+#include "flutter/fml/message_loop.h"
 #include "flutter/shell/common/platform_view.h"
 #include "flutter/shell/common/shell.h"
 #include "flutter/shell/common/switches.h"
@@ -26,31 +23,29 @@ const int kErrorExitCode = 255;
 
 // Checks whether the engine's main Dart isolate has no pending work.  If so,
 // then exit the given message loop.
-class ScriptCompletionTaskObserver : public base::MessageLoop::TaskObserver {
+class ScriptCompletionTaskObserver : public fml::TaskObserver {
  public:
-  ScriptCompletionTaskObserver(base::MessageLoop& main_message_loop)
-      : main_message_loop_(main_message_loop),
+  ScriptCompletionTaskObserver(ftl::RefPtr<ftl::TaskRunner> task_runner)
+      : main_task_runner_(std::move(task_runner)),
         prev_live_(false),
         last_error_(tonic::kNoError) {}
 
-  void WillProcessTask(const base::PendingTask& pending_task) override {}
-
-  void DidProcessTask(const base::PendingTask& pending_task) override {
+  void DidProcessTask() override {
     shell::TestRunner& test_runner = shell::TestRunner::Shared();
     shell::Engine& engine = test_runner.platform_view().engine();
 
     if (engine.GetLoadScriptError() != tonic::kNoError) {
       last_error_ = engine.GetLoadScriptError();
-      main_message_loop_.PostTask(FROM_HERE,
-                                  main_message_loop_.QuitWhenIdleClosure());
+      main_task_runner_->PostTask(
+          []() { fml::MessageLoop::GetCurrent().Terminate(); });
       return;
     }
 
     bool live = engine.UIIsolateHasLivePorts();
     if (prev_live_ && !live) {
       last_error_ = engine.GetUIIsolateLastError();
-      main_message_loop_.PostTask(FROM_HERE,
-                                  main_message_loop_.QuitWhenIdleClosure());
+      main_task_runner_->PostTask(
+          []() { fml::MessageLoop::GetCurrent().Terminate(); });
     }
     prev_live_ = live;
   }
@@ -58,7 +53,7 @@ class ScriptCompletionTaskObserver : public base::MessageLoop::TaskObserver {
   tonic::DartErrorHandleType last_error() { return last_error_; }
 
  private:
-  base::MessageLoop& main_message_loop_;
+  ftl::RefPtr<ftl::TaskRunner> main_task_runner_;
   bool prev_live_;
   tonic::DartErrorHandleType last_error_;
 };
@@ -78,25 +73,29 @@ int ConvertErrorTypeToExitCode(tonic::DartErrorHandleType error) {
 
 void RunNonInteractive(ftl::CommandLine initial_command_line,
                        bool run_forever) {
-  base::MessageLoop message_loop;
+  // This is a platform thread (i.e not one created by fml::Thread), so perform
+  // one time initialization.
+  fml::MessageLoop::EnsureInitializedForCurrentThread();
 
   shell::Shell::InitStandalone(initial_command_line);
 
   // Note that this task observer must be added after the observer that drains
   // the microtask queue.
-  ScriptCompletionTaskObserver task_observer(message_loop);
+  ScriptCompletionTaskObserver task_observer(
+      fml::MessageLoop::GetCurrent().GetTaskRunner());
   if (!run_forever) {
     blink::Threads::UI()->PostTask([&task_observer] {
-      base::MessageLoop::current()->AddTaskObserver(&task_observer);
+      fml::MessageLoop::GetCurrent().AddTaskObserver(&task_observer);
     });
   }
 
-  if (!shell::InitForTesting(std::move(initial_command_line))) {
+  if (!shell::InitForTesting(initial_command_line)) {
     shell::PrintUsage("sky_shell");
-    exit(1);
+    exit(EXIT_FAILURE);
+    return;
   }
 
-  message_loop.Run();
+  fml::MessageLoop::GetCurrent().Run();
 
   shell::TestRunner& test_runner = shell::TestRunner::Shared();
   tonic::DartErrorHandleType error =
@@ -117,8 +116,6 @@ int main(int argc, char* argv[]) {
   dart::bin::SetExecutableName(argv[0]);
   dart::bin::SetExecutableArguments(argc - 1, argv);
 
-  base::AtExitManager exit_manager;
-
   auto command_line = ftl::CommandLineFromArgcArgv(argc, argv);
 
   if (command_line.HasOption(shell::FlagForSwitch(shell::Switch::Help))) {