Simplify end of stream signaling again

Whenever a frame is queued to the shader, it's guaranteed that there will be a
subsequent `onInputFrameProcessed` callback, so we can pass on the
end-of-stream signal there.

PiperOrigin-RevId: 525850141

libraries/effect/src/main/java/androidx/media3/effect/ExternalTextureManager.java

@@ -57,11 +57,6 @@ import java.util.concurrent.atomic.AtomicInteger;
   // Read and written on the GL thread only.
   private boolean inputStreamEnded;
 
-  // TODO(b/278273122): Remove this flag and the signal end of input call after queueing a frame if
-  // all frames notify that they've been processed.
-
-  // Read and written on the GL thread only.
-  private boolean hasSignaledEndOfInput;
   // The frame that is sent downstream and is not done processing yet.
   // Set to null on any thread. Read and set to non-null on the GL thread only.
   @Nullable private volatile FrameInfo currentFrame;
@@ -135,7 +130,7 @@ import java.util.concurrent.atomic.AtomicInteger;
         () -> {
           currentFrame = null;
           if (inputStreamEnded && pendingFrames.isEmpty()) {
-            maybeSignalEndOfInput();
+            externalShaderProgram.signalEndOfCurrentInputStream();
           } else {
             maybeQueueFrameToExternalShaderProgram();
           }
@@ -183,7 +178,7 @@ import java.util.concurrent.atomic.AtomicInteger;
         () -> {
           inputStreamEnded = true;
           if (pendingFrames.isEmpty() && currentFrame == null) {
-            maybeSignalEndOfInput();
+            externalShaderProgram.signalEndOfCurrentInputStream();
           }
         });
   }
@@ -248,16 +243,6 @@ import java.util.concurrent.atomic.AtomicInteger;
             currentFrame.height),
         presentationTimeUs);
     checkStateNotNull(pendingFrames.remove());
-
-    if (inputStreamEnded && pendingFrames.isEmpty()) {
-      maybeSignalEndOfInput();
-    }
-  }
-
-  private void maybeSignalEndOfInput() {
-    if (!hasSignaledEndOfInput) {
-      hasSignaledEndOfInput = true;
-      externalShaderProgram.signalEndOfCurrentInputStream();
-    }
+    // If the queued frame is the last frame, end of stream will be signaled onInputFrameProcessed.
   }
 }