Enable MojoChannelMac feature by default.

Bug: 932175, 944985
Change-Id: I9a209965e3454e09a6914b2b19a8a44c4e841a90
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1539799Reviewed-by: Ken Rockot <rockot@google.com>
Commit-Queue: Robert Sesek <rsesek@chromium.org>
Cr-Commit-Position: refs/heads/master@{#672077}

mojo/public/cpp/platform/features.cc

@@ -12,7 +12,7 @@ namespace features {
 // transport mechanism for PlatformChannel. Otherwise, macOS defaults to using
 // ChannelPosix.
 const base::Feature kMojoChannelMac{"MojoChannelMac",
-                                    base::FEATURE_DISABLED_BY_DEFAULT};
+                                    base::FEATURE_ENABLED_BY_DEFAULT};
 #endif
 
 }  // namespace features