Update test code to use EncodedImage::Allocate

Bug: webrtc:9378
Change-Id: I2ea63b097b0263b264fbbcca295365781fcae621
Reviewed-on: https://webrtc-review.googlesource.com/c/122780
Commit-Queue: Niels Moller <nisse@webrtc.org>
Reviewed-by: Erik Språng <sprang@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#26690}
diff --git a/modules/video_coding/generic_encoder_unittest.cc b/modules/video_coding/generic_encoder_unittest.cc
index 4ea2506..0be0c75 100644
--- a/modules/video_coding/generic_encoder_unittest.cc
+++ b/modules/video_coding/generic_encoder_unittest.cc
@@ -82,7 +82,6 @@
       {delay_ms, kDefaultOutlierFrameSizePercent});
   callback.OnFrameRateChanged(kFramerate);
   int s, i;
-  std::vector<uint8_t> frame_data(max_frame_size);
   std::vector<std::vector<FrameType>> result(num_streams);
   for (s = 0; s < num_streams; ++s)
     callback.OnTargetBitrateChanged(average_frame_sizes[s] * kFramerate, s);
@@ -95,7 +94,7 @@
 
       EncodedImage image;
       CodecSpecificInfo codec_specific;
-      image.set_buffer(frame_data.data(), frame_data.size());
+      image.Allocate(max_frame_size);
       image.set_size(FrameSize(min_frame_size, max_frame_size, s, i));
       image.capture_time_ms_ = current_timestamp;
       image.SetTimestamp(static_cast<uint32_t>(current_timestamp * 90));
@@ -189,9 +188,9 @@
   EncodedImage image;
   CodecSpecificInfo codec_specific;
   int64_t timestamp = 1;
-  uint8_t frame_data[500];
-  image.set_buffer(frame_data, sizeof(frame_data));
-  image.set_size(sizeof(frame_data));
+  constexpr size_t kFrameSize = 500;
+  image.Allocate(kFrameSize);
+  image.set_size(kFrameSize);
   image.capture_time_ms_ = timestamp;
   image.SetTimestamp(static_cast<uint32_t>(timestamp * 90));
   codec_specific.codecType = kVideoCodecGeneric;
@@ -222,9 +221,9 @@
   const int64_t kEncodeStartDelayMs = 2;
   const int64_t kEncodeFinishDelayMs = 10;
   int64_t timestamp = 1;
-  uint8_t frame_data[500];
-  image.set_buffer(frame_data, sizeof(frame_data));
-  image.set_size(sizeof(frame_data));
+  constexpr size_t kFrameSize = 500;
+  image.Allocate(kFrameSize);
+  image.set_size(kFrameSize);
   image.capture_time_ms_ = timestamp;
   image.SetTimestamp(static_cast<uint32_t>(timestamp * 90));
   codec_specific.codecType = kVideoCodecGeneric;