Reland "Disable the CompilerDispatcher if we don't have idle time"

test/unittests/compiler-dispatcher/compiler-dispatcher-unittest.cc

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler-dispatcher/compiler-dispatcher.h"
 
 #include "include/v8-platform.h"
 #include "src/compiler-dispatcher/compiler-dispatcher-job.h"
 #include "src/flags.h"
 #include "src/handles.h"
 #include "src/objects-inl.h"
 #include "test/unittests/compiler-dispatcher/compiler-dispatcher-helper.h"
 #include "test/unittests/test-utils.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace v8 {
 namespace internal {
 
-typedef TestWithContext CompilerDispatcherTest;
+class CompilerDispatcherTest : public TestWithContext {
+ public:
+  CompilerDispatcherTest() = default;
+  ~CompilerDispatcherTest() override = default;
+
+  static void SetUpTestCase() {
+    old_flag_ = i::FLAG_ignition;
+    i::FLAG_compiler_dispatcher = true;
+    TestWithContext::SetUpTestCase();
+  }
+
+  static void TearDownTestCase() {
+    TestWithContext::TearDownTestCase();
+    i::FLAG_compiler_dispatcher = old_flag_;
+  }
+
+ private:
+  static bool old_flag_;
+
+  DISALLOW_COPY_AND_ASSIGN(CompilerDispatcherTest);
+};
+
+bool CompilerDispatcherTest::old_flag_;
 
 namespace {
 
 class MockPlatform : public v8::Platform {
  public:
   MockPlatform() : task_(nullptr), time_(0.0), time_step_(0.0) {}
   ~MockPlatform() override = default;
 
   void CallOnBackgroundThread(Task* task,
                               ExpectedRuntime expected_runtime) override {
@@ skipping 168 matching lines @@
   // to finish compiling the function.
   platform.RunIdleTask(1000.0, 0.0);
 
   ASSERT_FALSE(dispatcher.IsEnqueued(shared));
   ASSERT_FALSE(shared->is_compiled());
   ASSERT_FALSE(try_catch.HasCaught());
 }
 
 }  // namespace internal
 }  // namespace v8