mac: Stop setting BuildMachineOSBuild in Info.plists

This key's value makes the build output machine-dependent, and it's not
clear that we need to set it. So try not setting it.

Keep setting it in iOS builds, since the key might be used by the
app store submission process, and the iOS build doesn't use a hermetic
Xcode anyways.

Bug: 1149401
Change-Id: I86f804e60f4ba1a9dcefa46cd3f14910b654ae9d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2540578
Auto-Submit: Nico Weber <thakis@chromium.org>
Commit-Queue: Robert Sesek <rsesek@chromium.org>
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Cr-Commit-Position: refs/heads/master@{#827846}

build/config/mac/BuildInfo.plist

@@ -2,8 +2,6 @@
 <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
 <plist version="1.0">
 <dict>
-  <key>BuildMachineOSBuild</key>
-  <string>${BUILD_MACHINE_OS_BUILD}</string>
   <key>DTCompiler</key>
   <string>${GCC_VERSION}</string>
   <key>DTSDKBuild</key>

build/config/mac/base_rules.gni

@@ -220,7 +220,6 @@ template("info_plist") {
     }
 
     substitutions = [
-      "BUILD_MACHINE_OS_BUILD=$machine_os_build",
       "EXECUTABLE_NAME=$executable_name",
       "GCC_VERSION=com.apple.compilers.llvm.clang.1_0",
       "PRODUCT_NAME=$executable_name",
@@ -233,7 +232,10 @@ template("info_plist") {
         "CHROMIUM_MIN_SYSTEM_VERSION=$mac_min_system_version",
       ]
     } else if (is_ios) {
-      substitutions += [ "IOS_DEPLOYMENT_TARGET=$ios_deployment_target" ]
+      substitutions += [
+        "BUILD_MACHINE_OS_BUILD=$machine_os_build",
+        "IOS_DEPLOYMENT_TARGET=$ios_deployment_target",
+      ]
     }
     if (defined(invoker.extra_substitutions)) {
       substitutions += invoker.extra_substitutions