[null-safety] migrate to _almost_ null safety (flutter#162)

Remove record/replay functionality and update to almost null-safety.

Author: Jonah Williams

analysis_options.yaml

@@ -1,4 +1,6 @@
 analyzer:
+  enable-experiment:
+    - non-nullable
   strong-mode:
     implicit-casts: false
     implicit-dynamic: false

appveyor.yml

@@ -11,4 +11,4 @@ install:
 build: off
 
 test_script:
-  - pub run test -j1
+  - pub run --enable-experiment=non-nullable test -j1

dev/bots/travis_script.sh

@@ -11,10 +11,10 @@ elif [[ "$SHARD" == "analyze" ]]; then
   for package in "${PACKAGES[@]}"; do
     echo "Analyzing packages/$package"
     cd $ROOT/packages/$package
-    dartanalyzer --options=$ROOT/analysis_options.yaml . || exit $?
+    dartanalyzer --enable-experiment=non-nullable --options=$ROOT/analysis_options.yaml . || exit $?
   done
 else
   # tests shard
   cd $ROOT/packages/file
-  pub run test -j1 -rexpanded || exit $?
+  pub run --enable-experiment=non-nullable test -j1 -rexpanded || exit $?
 fi

packages/file/CHANGELOG.md

@@ -1,6 +1,8 @@
-#### 5.2.2-dev
+#### 6.0.0-nullsafety
 
-* Made `MemoryRandomAccessFile` and `MemoryFile.openWrite` handle the file
+* Update to null safety.
+* Remove record/replay functionality.
+* Made `MemoryRandomAccessFile` and `MemoryFile.openWrite` handle the file.
   being removed or renamed while open.
 * Fixed incorrect formatting in `NoMatchingInvocationError.toString()`.
 * Fixed more test flakiness.

packages/file/lib/chroot.dart

@@ -2,5 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart=2.10
+
 /// A file system that provides a view into _another_ `FileSystem` via a path.
 export 'src/backends/chroot.dart';

packages/file/lib/file.dart

@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart=2.10
+
 /// Core interfaces containing the abstract `FileSystem` interface definition
 /// and all associated types used by `FileSystem`.
 export 'src/forwarding.dart';

packages/file/lib/local.dart

@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart=2.10
+
 /// A local file system implementation. This relies on the use of `dart:io`
 /// and is thus not suitable for use in the browser.
 export 'src/backends/local.dart';

packages/file/lib/memory.dart

@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart=2.10
+
 /// An implementation of `FileSystem` that exists entirely in memory with an
 /// internal representation loosely based on the Filesystem Hierarchy Standard.
 export 'src/backends/memory.dart';

packages/file/lib/record_replay.dart

@@ -2,6 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart=2.10
 library file.src.backends.chroot;
 
 import 'dart:async';