Revert GlobalConfig to use gflags again (#147)

Summary:
X-link: facebookincubator/velox#12503

Pull Request resolved: #147

Reverts the use of GlobalConfig and switches back to using gflags. Unfortunately using globalConfig requires us to call translateFlagsToGlobalConfig immediately after ParseCommandLineFlags to initialize it right. Because other libraries also use velox , transitively there are many such places. Thus reverting this change till we figure out a better mechanism to remove gflags dependencies.

Reviewed By: amitkdutta

Differential Revision: D70463150

fbshipit-source-id: 7bbd33818666c1f4235ef2e33496fa5cd8cf6a6e

Author: Krishna Pai

dwio/nimble/common/tests/VectorTests.cpp

@@ -17,15 +17,22 @@
 #include "dwio/nimble/common/Vector.h"
 #include "velox/common/memory/Memory.h"
 
+DECLARE_bool(velox_enable_memory_usage_track_in_default_memory_pool);
+
 using namespace ::facebook;
 
-TEST(VectorTests, InitializerList) {
-  auto pool = velox::memory::deprecatedAddDefaultLeafMemoryPool();
-  nimble::Vector<int32_t> v1(pool.get(), {3, 4});
-  EXPECT_EQ(2, v1.size());
-  EXPECT_EQ(3, v1[0]);
-  EXPECT_EQ(4, v1[1]);
-}
+class VectorTests : public ::testing::Test {
+ protected:
+  static void SetUpTestCase() {
+    FLAGS_velox_enable_memory_usage_track_in_default_memory_pool = true;
+  }
+
+  void SetUp() override {
+    pool_ = facebook::velox::memory::deprecatedAddDefaultLeafMemoryPool();
+  }
+
+  std::shared_ptr<velox::memory::MemoryPool> pool_;
+};
 
 TEST(VectorTests, FromRange) {
   auto pool = velox::memory::deprecatedAddDefaultLeafMemoryPool();