Update platform files and gitignore (#60407)

dev/benchmarks/macrobenchmarks/.gitignore

+lib/generated_plugin_registrant.dart

dev/benchmarks/macrobenchmarks/ios/Flutter/Debug.xcconfig

+#include "Pods/Target Support Files/Pods-Runner/Pods-Runner.debug.xcconfig"
 #include "Generated.xcconfig"

dev/benchmarks/macrobenchmarks/ios/Flutter/Release.xcconfig

+#include "Pods/Target Support Files/Pods-Runner/Pods-Runner.release.xcconfig"
 #include "Generated.xcconfig"

dev/benchmarks/macrobenchmarks/ios/Podfile

+# Uncomment this line to define a global platform for your project
+# platform :ios, '9.0'
+
+# CocoaPods analytics sends network stats synchronously affecting flutter build latency.
+ENV['COCOAPODS_DISABLE_STATS'] = 'true'
+
+project 'Runner', {
+  'Debug' => :debug,
+  'Profile' => :release,
+  'Release' => :release,
+}
+
+def flutter_root
+  generated_xcode_build_settings_path = File.expand_path(File.join('..', 'Flutter', 'Generated.xcconfig'), __FILE__)
+  unless File.exist?(generated_xcode_build_settings_path)
+    raise "#{generated_xcode_build_settings_path} must exist. If you're running pod install manually, make sure flutter pub get is executed first"
+  end
+
+  File.foreach(generated_xcode_build_settings_path) do |line|
+    matches = line.match(/FLUTTER_ROOT\=(.*)/)
+    return matches[1].strip if matches
+  end
+  raise "FLUTTER_ROOT not found in #{generated_xcode_build_settings_path}. Try deleting Generated.xcconfig, then run flutter pub get"
+end
+
+require File.expand_path(File.join('packages', 'flutter_tools', 'bin', 'podhelper'), flutter_root)
+
+flutter_ios_podfile_setup
+
+target 'Runner' do
+  flutter_install_all_ios_pods File.dirname(File.realpath(__FILE__))
+end
+
+post_install do |installer|
+  installer.pods_project.targets.each do |target|
+    flutter_additional_ios_build_settings(target)
+  end
+end

dev/benchmarks/macrobenchmarks/macos/Podfile

+platform :osx, '10.11'
+
+# CocoaPods analytics sends network stats synchronously affecting flutter build latency.
+ENV['COCOAPODS_DISABLE_STATS'] = 'true'
+
+project 'Runner', {
+  'Debug' => :debug,
+  'Profile' => :release,
+  'Release' => :release,
+}
+
+def parse_KV_file(file, separator='=')
+  file_abs_path = File.expand_path(file)
+  if !File.exists? file_abs_path
+    return [];
+  end
+  pods_ary = []
+  skip_line_start_symbols = ["#", "/"]
+  File.foreach(file_abs_path) { |line|
+      next if skip_line_start_symbols.any? { |symbol| line =~ /^\s*#{symbol}/ }
+      plugin = line.split(pattern=separator)
+      if plugin.length == 2
+        podname = plugin[0].strip()
+        path = plugin[1].strip()
+        podpath = File.expand_path("#{path}", file_abs_path)
+        pods_ary.push({:name => podname, :path => podpath});
+      else
+        puts "Invalid plugin specification: #{line}"
+      end
+  }
+  return pods_ary
+end
+
+def pubspec_supports_macos(file)
+  file_abs_path = File.expand_path(file)
+  if !File.exists? file_abs_path
+    return false;
+  end
+  File.foreach(file_abs_path) { |line|
+    return true if line =~ /^\s*macos:/
+  }
+  return false
+end
+
+target 'Runner' do
+  use_frameworks!
+  use_modular_headers!
+
+  # Prepare symlinks folder. We use symlinks to avoid having Podfile.lock
+  # referring to absolute paths on developers' machines.
+  ephemeral_dir = File.join('Flutter', 'ephemeral')
+  symlink_dir = File.join(ephemeral_dir, '.symlinks')
+  symlink_plugins_dir = File.join(symlink_dir, 'plugins')
+  system("rm -rf #{symlink_dir}")
+  system("mkdir -p #{symlink_plugins_dir}")
+
+  # Flutter Pods
+  generated_xcconfig = parse_KV_file(File.join(ephemeral_dir, 'Flutter-Generated.xcconfig'))
+  if generated_xcconfig.empty?
+    puts "Flutter-Generated.xcconfig must exist. If you're running pod install manually, make sure flutter packages get is executed first."
+  end
+  generated_xcconfig.map { |p|
+    if p[:name] == 'FLUTTER_FRAMEWORK_DIR'
+      symlink = File.join(symlink_dir, 'flutter')
+      File.symlink(File.dirname(p[:path]), symlink)
+      pod 'FlutterMacOS', :path => File.join(symlink, File.basename(p[:path]))
+    end
+  }
+
+  # Plugin Pods
+  plugin_pods = parse_KV_file('../.flutter-plugins')
+  plugin_pods.map { |p|
+    symlink = File.join(symlink_plugins_dir, p[:name])
+    File.symlink(p[:path], symlink)
+    if pubspec_supports_macos(File.join(symlink, 'pubspec.yaml'))
+      pod p[:name], :path => File.join(symlink, 'macos')
+    end
+  }
+end
+
+# Prevent Cocoapods from embedding a second Flutter framework and causing an error with the new Xcode build system.
+install! 'cocoapods', :disable_input_output_paths => true