media/gpu/vea_tests: Decrease the number of encoders in concurrent encoder test cases

The number of encoders is three in the concurrent encoder test
case in video_encode_accelerator_tests. In the test case and
2160p encoding, creating shared memory for input frames fails on
lower end devices due to a shortage of allowed handles.
Decreasing the number of encoders should mitigate the fatal.

Bug: b:170790027
Test: video_encode_accelerator_tests on cyan
Change-Id: I669f026729c355e117b29389f08f66c05bcfa76f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2532541Reviewed-by: David Staessens <dstaessens@chromium.org>
Commit-Queue: Hirokazu Honda <hiroh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#827707}

media/gpu/video_encode_accelerator_tests.cc

@@ -277,8 +277,11 @@ TEST_F(VideoEncoderTest, FlushAtEndOfStream_MultipleOutstandingEncodes) {
 
 // Encode multiple videos simultaneously from start to finish.
 TEST_F(VideoEncoderTest, FlushAtEndOfStream_MultipleConcurrentEncodes) {
-  // The minimal number of concurrent encoders we expect to be supported.
-  constexpr size_t kMinSupportedConcurrentEncoders = 3;
+  // Run two encoders for larger resolutions to avoid creating shared memory
+  // buffers during the test on lower end devices.
+  constexpr gfx::Size k1080p(1920, 1080);
+  const size_t kMinSupportedConcurrentEncoders =
+      g_env->Video()->Resolution().GetArea() >= k1080p.GetArea() ? 2 : 3;
 
   auto config = GetDefaultConfig();
   std::vector<std::unique_ptr<VideoEncoder>> encoders(