Add privateuseone flags for c10::EventFlag (#121118)

Fixes #117341
Pull Request resolved: #121118
Approved by: https://github.com/albanD

aten/src/ATen/hip/impl/HIPGuardImplMasqueradingAsCUDA.h

@@ -120,11 +120,9 @@ struct HIPGuardImplMasqueradingAsCUDA final : public c10::impl::DeviceGuardImplI
     auto hip_flag = hipEventDefault;
     switch (flag) {
       case EventFlag::PYTORCH_DEFAULT:
-      case EventFlag::HIP_EVENT_DISABLE_TIMING:
         hip_flag = hipEventDisableTiming;
         break;
       case EventFlag::BACKEND_DEFAULT:
-      case EventFlag::HIP_EVENT_DEFAULT:
         hip_flag = hipEventDefault;
         break;
       default:

c10/core/impl/DeviceGuardImplInterface.h

@@ -21,23 +21,16 @@ class DataPtr;
  * PYTORCH_DEFAULT and BACKEND_DEFAULT are valid for all backends. The
  * BACKEND_DEFAULT is what a particular backend would select if no
  * flags were given. PYTORCH_DEFAULT is the PyTorch's framework default
- * choice for events on that backend, which may not be the same. For example,
- * when PyTorch creates a CUDA event it sets the flag
- * CUDA_EVENT_DISABLING_TIMING by default to improve performance.
+ * choice for events on that backend, which may not be the same.
  *
  * The mapping of PYTORCH_DEFAULT and BACKEND_DEFAULT is done by each
- * backend implementation. Backend-specific flags, like CUDA_EVENT_DEFAULT,
- * should map one-to-one with actual event flags for those backends.
+ * backend implementation.
  */
 enum class EventFlag {
+  // Disable timing
   PYTORCH_DEFAULT,
+  // Enable timing
   BACKEND_DEFAULT,
-  // CUDA flags
-  CUDA_EVENT_DEFAULT,
-  CUDA_EVENT_DISABLE_TIMING, // PyTorch-default for CUDA
-  // HIP flags
-  HIP_EVENT_DEFAULT,
-  HIP_EVENT_DISABLE_TIMING, // PyTorch-default for HIP
   // FOR TESTING ONLY
   INVALID
 };

c10/cuda/impl/CUDAGuardImpl.h

@@ -83,11 +83,9 @@ struct CUDAGuardImpl final : public c10::impl::DeviceGuardImplInterface {
     auto cuda_flag = cudaEventDefault;
     switch (flag) {
       case EventFlag::PYTORCH_DEFAULT:
-      case EventFlag::CUDA_EVENT_DISABLE_TIMING:
         cuda_flag = cudaEventDisableTiming;
         break;
       case EventFlag::BACKEND_DEFAULT:
-      case EventFlag::CUDA_EVENT_DEFAULT:
         cuda_flag = cudaEventDefault;
         break;
       default: