[Android] Remove old onStats

Differential Revision: D73292616

Pull Request resolved: #10312

Author: kirklandsign

examples/demo-apps/android/LlamaDemo/README.md

@@ -135,8 +135,8 @@ Ensure you have the following functions in your callback class that you provided
   }
 
   @Override
-  public void onStats(float tps) {
-    //...tps (tokens per second) stats is provided by framework
+  public void onStats(String stats) {
+    //... will be a json. See extension/llm/stats.h for the field definitions
   }
 
 ```

extension/android/executorch_android/src/main/java/org/pytorch/executorch/extension/llm/LlmCallback.java

@@ -28,17 +28,6 @@ public interface LlmCallback {
   @DoNotStrip
   public void onResult(String result);
 
-  /**
-   * Called when the statistics for the generate() is available.
-   *
-   * Note: This is a deprecated API and will be removed in the future. Please use onStats(String stats)
-   *
-   * @param tps Tokens/second for generated tokens.
-   */
-  @Deprecated
-  @DoNotStrip
-  default public void onStats(float tps) {}
-
   /**
    * Called when the statistics for the generate() is available.
    *
@@ -48,5 +37,5 @@ default public void onStats(float tps) {}
    * @param stats JSON string containing the statistics for the generate()
    */
   @DoNotStrip
-  default public void onStats(String stats) {}
+  default void onStats(String stats) {}
 }

extension/android/jni/jni_layer_llama.cpp

@@ -100,14 +100,6 @@ class ExecuTorchLlmCallbackJni
 
   void onStats(const llm::Stats& result) const {
     static auto cls = ExecuTorchLlmCallbackJni::javaClassStatic();
-    static const auto tps_method = cls->getMethod<void(jfloat)>("onStats");
-    double eval_time =
-        (double)(result.inference_end_ms - result.prompt_eval_end_ms);
-
-    float tps = result.num_generated_tokens / eval_time *
-        result.SCALING_FACTOR_UNITS_PER_SECOND;
-    tps_method(self(), tps);
-
     static const auto on_stats_method =
         cls->getMethod<void(facebook::jni::local_ref<jstring>)>("onStats");
     on_stats_method(