onEndFrame JNI (flutter/engine#18867)

* onEndFrame JNI

* beginFrame brief change

engine/src/flutter/shell/platform/android/io/flutter/embedding/engine/FlutterJNI.java

@@ -810,6 +810,17 @@ public class FlutterJNI {
     }
     platformViewsController.onBeginFrame();
   }
+
+  @SuppressWarnings("unused")
+  @UiThread
+  public void onEndFrame() {
+    ensureRunningOnMainThread();
+    if (platformViewsController == null) {
+      throw new RuntimeException(
+          "platformViewsController must be set before attempting to end the frame");
+    }
+    platformViewsController.onEndFrame();
+  }
   // ----- End Engine Lifecycle Support ----
 
   // @SuppressWarnings("unused")

engine/src/flutter/shell/platform/android/io/flutter/plugin/platform/PlatformViewsController.java

@@ -545,4 +545,8 @@ public class PlatformViewsController implements PlatformViewsAccessibilityDelega
   public void onBeginFrame() {
     // TODO: Implement this method. https://github.com/flutter/flutter/issues/58288
   }
+
+  public void onEndFrame() {
+    // TODO: Implement this method. https://github.com/flutter/flutter/issues/58288
+  }
 }

engine/src/flutter/shell/platform/android/jni/platform_view_android_jni.h

@@ -137,6 +137,14 @@ class PlatformViewAndroidJNI {
   /// @note       Must be called from the platform thread.
   ///
   virtual void FlutterViewBeginFrame() = 0;
+
+  //----------------------------------------------------------------------------
+  /// @brief      Indicates that the current frame ended.
+  ///             It's used to clean up state.
+  ///
+  /// @note       Must be called from the platform thread.
+  ///
+  virtual void FlutterViewEndFrame() = 0;
 };
 
 }  // namespace flutter

engine/src/flutter/shell/platform/android/platform_view_android_jni_impl.cc

@@ -82,6 +82,8 @@ static jmethodID g_on_engine_restart_method = nullptr;
 
 static jmethodID g_on_begin_frame_method = nullptr;
 
+static jmethodID g_on_end_frame_method = nullptr;
+
 static jmethodID g_attach_to_gl_context_method = nullptr;
 
 static jmethodID g_update_tex_image_method = nullptr;
@@ -717,6 +719,14 @@ bool PlatformViewAndroid::Register(JNIEnv* env) {
     return false;
   }
 
+  g_on_end_frame_method =
+      env->GetMethodID(g_flutter_jni_class->obj(), "onEndFrame", "()V");
+
+  if (g_on_end_frame_method == nullptr) {
+    FML_LOG(ERROR) << "Could not locate onEndFrame method";
+    return false;
+  }
+
   g_on_display_overlay_surface_method = env->GetMethodID(
       g_flutter_jni_class->obj(), "onDisplayOverlaySurface", "(IIIII)V");
 
@@ -1046,4 +1056,17 @@ void PlatformViewAndroidJNIImpl::FlutterViewBeginFrame() {
   FML_CHECK(CheckException(env));
 }
 
+void PlatformViewAndroidJNIImpl::FlutterViewEndFrame() {
+  JNIEnv* env = fml::jni::AttachCurrentThread();
+
+  auto java_object = java_object_.get(env);
+  if (java_object.is_null()) {
+    return;
+  }
+
+  env->CallVoidMethod(java_object.obj(), g_on_end_frame_method);
+
+  FML_CHECK(CheckException(env));
+}
+
 }  // namespace flutter

engine/src/flutter/shell/platform/android/platform_view_android_jni_impl.h

@@ -64,6 +64,8 @@ class PlatformViewAndroidJNIImpl final : public PlatformViewAndroidJNI {
 
   void FlutterViewBeginFrame() override;
 
+  void FlutterViewEndFrame() override;
+
  private:
   // Reference to FlutterJNI object.
   const fml::jni::JavaObjectWeakGlobalRef java_object_;

engine/src/flutter/shell/platform/android/test/io/flutter/embedding/engine/FlutterJNITest.java

@@ -96,4 +96,19 @@ public class FlutterJNITest {
     // --- Verify Results ---
     verify(platformViewsController, times(1)).onBeginFrame();
   }
+
+  @Test
+  public void onEndFrame__callsPlatformViewsController() {
+    PlatformViewsController platformViewsController = mock(PlatformViewsController.class);
+
+    // --- Test Setup ---
+    FlutterJNI flutterJNI = new FlutterJNI();
+    flutterJNI.setPlatformViewsController(platformViewsController);
+
+    // --- Execute Test ---
+    flutterJNI.onEndFrame();
+
+    // --- Verify Results ---
+    verify(platformViewsController, times(1)).onEndFrame();
+  }
 }