Remove unused using-declarations

Signed-off-by: cyy <cyyever@outlook.com>

Author: cyyever

backends/aoti/slim/factory/test/test_from_etensor.cpp

@@ -20,8 +20,6 @@
 
 namespace executorch::backends::aoti::slim {
 
-using executorch::runtime::Error;
-using executorch::runtime::TensorShapeDynamism;
 using executorch::runtime::etensor::ScalarType;
 using executorch::runtime::testing::TensorFactory;
 

backends/apple/coreml/runtime/delegate/executorch_operations.mm

@@ -13,7 +13,6 @@
 #import <memory>
 
 namespace executorch::core_ml_backend_delegate {
-  using executorch::runtime::get_backend_class;
 
 static std::unique_ptr<executorch::backends::coreml::CoreMLBackendDelegate> backendInterfaceLazy_;
 

backends/apple/coreml/runtime/test/CoreMLBackendDelegateTests.mm

@@ -18,7 +18,6 @@
 static constexpr size_t kRuntimeMemorySize = 50 * 1024U * 1024U; // 50 MB
 
 using namespace executorch::runtime;
-using executorch::runtime::testing::TensorFactory;
 
 namespace {
 // TODO: Move the following methods to a utility class, so that it can be shared with `executor_runner.main.mm`

backends/apple/coreml/runtime/test/coreml_backend_options_test.cpp

@@ -13,7 +13,6 @@
 #include <gtest/gtest.h>
 
 using executorch::backends::coreml::LoadOptionsBuilder;
-using executorch::runtime::BackendOption;
 using executorch::runtime::Error;
 using executorch::runtime::kMaxOptionValueLength;
 using executorch::runtime::LoadBackendOptionsMap;

backends/apple/metal/runtime/metal_backend.cpp

@@ -135,21 +135,17 @@ get_metal_backend_init_per_method_stats() {
 using namespace std;
 using namespace aoti;
 
-using executorch::aten::ScalarType;
 using executorch::runtime::ArrayRef;
-using executorch::runtime::Backend;
 using executorch::runtime::BackendExecutionContext;
 using executorch::runtime::BackendInitContext;
 using executorch::runtime::CompileSpec;
 using executorch::runtime::DelegateHandle;
 using executorch::runtime::Error;
 using executorch::runtime::EValue;
 using executorch::runtime::FreeableBuffer;
-using executorch::runtime::MemoryAllocator;
 using executorch::runtime::NamedDataMap;
 using executorch::runtime::Result;
 using executorch::runtime::Span;
-using executorch::runtime::etensor::Tensor;
 
 class ET_EXPERIMENTAL MetalBackend final
     : public ::executorch::runtime::BackendInterface {

backends/cadence/fusion_g3/operators/op_dequantize.cpp

@@ -20,7 +20,6 @@
 
 using ::executorch::aten::ScalarType;
 using ::executorch::aten::Tensor;
-using ::executorch::runtime::Error;
 using ::executorch::runtime::KernelRuntimeContext;
 
 template <typename T>

backends/cadence/fusion_g3/operators/op_permute_copy.cpp

@@ -18,7 +18,6 @@
 using ::executorch::aten::ArrayRef;
 using ::executorch::aten::IntArrayRef;
 using ::executorch::aten::ScalarType;
-using ::executorch::aten::SizesType;
 using ::executorch::aten::Tensor;
 using ::executorch::runtime::Error;
 using ::executorch::runtime::KernelRuntimeContext;

backends/cadence/fusion_g3/operators/op_transpose_copy.cpp

@@ -16,7 +16,6 @@
 #include <executorch/runtime/kernel/kernel_includes.h>
 
 using ::executorch::aten::ScalarType;
-using ::executorch::aten::SizesType;
 using ::executorch::aten::Tensor;
 using ::executorch::runtime::Error;
 using ::executorch::runtime::KernelRuntimeContext;

backends/cadence/fusion_g3/operators/tests/test_op_add.cpp

@@ -28,9 +28,6 @@ using ::executorch::aten::Scalar;
 using ::executorch::aten::ScalarType;
 using ::executorch::aten::Tensor;
 using ::executorch::aten::TensorImpl;
-using ::executorch::runtime::Error;
-using ::executorch::runtime::KernelRuntimeContext;
-using ::executorch::runtime::runtime_init;
 using ::executorch::runtime::testing::TensorFactory;
 
 class FusionG3OperatorTest : public OperatorTest {

backends/cadence/generic/operators/op_conv1d.cpp

@@ -15,7 +15,6 @@ namespace generic {
 namespace native {
 
 using ::executorch::aten::IntArrayRef;
-using ::executorch::aten::ScalarType;
 using ::executorch::aten::Tensor;
 using ::executorch::runtime::KernelRuntimeContext;