[macOS] Speculatively re-enable InCaptureConvertToNv12 with 5 buffers.

This is part of investigating https://crbug.com/1148964.
It may or may not cause Canary crashes again. We are monitoring crashes.

TBR=handellm@google.com

Bug: chromium:1148964
Change-Id: I5e778cd024f126811319ba750cb46adbdf3ce090
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2550206Reviewed-by: Henrik Boström <hbos@chromium.org>
Commit-Queue: Henrik Boström <hbos@chromium.org>
Cr-Commit-Position: refs/heads/master@{#829278}

media/capture/video/mac/sample_buffer_transformer_mac.cc

@@ -16,7 +16,7 @@
 namespace media {
 
 const base::Feature kInCaptureConvertToNv12{"InCaptureConvertToNv12",
-                                            base::FEATURE_DISABLED_BY_DEFAULT};
+                                            base::FEATURE_ENABLED_BY_DEFAULT};
 
 const base::Feature kInCaptureConvertToNv12WithPixelTransfer{
     "InCaptureConvertToNv12WithPixelTransfer",
@@ -27,7 +27,7 @@ const base::Feature kInCaptureConvertToNv12WithLibyuv{
 
 namespace {
 
-constexpr size_t kDefaultBufferPoolSize = 10;
+constexpr size_t kDefaultBufferPoolSize = 5;
 
 // NV12 a.k.a. 420v
 constexpr OSType kPixelFormatNv12 =

media/capture/video/mac/sample_buffer_transformer_mac_unittest.mm

@@ -408,8 +408,8 @@ INSTANTIATE_TEST_SUITE_P(SampleBufferTransformerTest,
                          TestParametersOSTypeToString);
 
 TEST(SampleBufferTransformerAutoReconfigureTest,
-     AutoReconfigureIsDisabledByDefault) {
-  EXPECT_FALSE(SampleBufferTransformer::CreateIfAutoReconfigureEnabled());
+     AutoReconfigureIsEnabledByDefault) {
+  EXPECT_TRUE(SampleBufferTransformer::CreateIfAutoReconfigureEnabled());
 }
 
 TEST(SampleBufferTransformerAutoReconfigureTest,