Fix explicit padding when pool residuals are used. Match the pool residual...

Fix explicit padding when pool residuals are used. Match the pool residual convolution to the depthwise convolution to ensure the output tensors of both are of the same size.

PiperOrigin-RevId: 370971019

research/object_detection/models/feature_map_generators.py

@@ -467,9 +467,11 @@ def multi_resolution_feature_maps(feature_map_layout, depth_multiplier,
             stride=1,
             scope=layer_name)
         if pool_residual and pre_layer_depth == depth_fn(layer_depth):
+          if use_explicit_padding:
+            pre_layer = ops.fixed_padding(pre_layer, conv_kernel_size)
           feature_map += slim.avg_pool2d(
-              pre_layer, [3, 3],
-              padding='SAME',
+              pre_layer, [conv_kernel_size, conv_kernel_size],
+              padding=padding,
               stride=2,
               scope=layer_name + '_pool')
       else: