Repository: flutter
Issue: Attempting to install a non-code-signed iOS app should provide a meaningful error
Labels: platform-ios,tool,a: quality,P3,team-ios,triaged-ios

```
flutter build ios --no-codesign
flutter install -v
```

Will produce a lot of logs that end with:

```
Install failed

#0      throwToolExit (package:flutter_tools/src/base/common.dart:26:3)
#1      InstallCommand.runCommand (package:flutter_tools/src/commands/install.dart:44:7)
<asynchronous suspension>
#2      FlutterCommand.verifyThenRunCommand (package:flutter_tools/src/runner/flutter_command.dart:401:18)
#3      _asyncThenWrapperHelper.<anonymous closure> (dart:async/runtime/libasync_patch.dart:77:64)
#4      _rootRunUnary (dart:async/zone.dart:1132:38)
#5      _CustomZone.runUnary (dart:async/zone.dart:1029:19)
#6      _FutureListener.handleValue (dart:async/future_impl.dart:129:18)
#7      Future._propagateToListeners.handleValueCallback (dart:async/future_impl.dart:642:45)
#8      Future._propagateToListeners (dart:async/future_impl.dart:671:32)
#9      Future._complete (dart:async/future_impl.dart:476:7)
#10     _SyncCompleter.complete (dart:async/future_impl.dart:51:12)
#11     _AsyncAwaitCompleter.complete.<anonymous closure> (dart:async/runtime/libasync_patch.dart:33:20)
#12     _rootRun (dart:async/zone.dart:1124:13)
#13     _CustomZone.run (dart:async/zone.dart:1021:19)
#14     _CustomZone.bindCallback.<anonymous closure> (dart:async/zone.dart:947:23)
#15     _microtaskLoop (dart:async/schedule_microtask.dart:41:21)
#16     _startMicrotaskLoop (dart:async/schedule_microtask.dart:50:5)
#17     _runPendingImmediateCallback (dart:isolate/runtime/libisolate_patch.dart:115:13)
#18     _RawReceivePortImpl._handleMessage (dart:isolate/runtime/libisolate_patch.dart:172:5)
```

It would be very nice if attempting to install a non-code-signed app would produce a meaningful error along the lines of "cannot install a non-code-signed app." I know this is a silly mistake, but it could be very useful for novices to provide a little bit of info here.

---------

```
❯ flutter doctor -v
[✓] Flutter (Channel beta, v1.0.0, on Mac OS X 10.14.2 18C54, locale en-US)
    • Flutter version 1.0.0 at /Users/maxlapides/flutter
    • Framework revision 5391447fae (3 weeks ago), 2018-11-29 19:41:26 -0800
    • Engine revision 7375a0f414
    • Dart version 2.1.0 (build 2.1.0-dev.9.4 f9ebf21297)

[✓] Android toolchain - develop for Android devices (Android SDK 27.0.3)
    • Android SDK at /Users/maxlapides/Library/Android/sdk
    • Android NDK location not configured (optional; useful for native profiling support)
    • Platform android-27, build-tools 27.0.3
    • ANDROID_HOME = /Users/maxlapides/Library/Android/sdk
    • Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1136-b06)
    • All Android licenses accepted.

[✓] iOS toolchain - develop for iOS devices (Xcode 10.1)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 10.1, Build version 10B61
    • ios-deploy 1.9.4
    • CocoaPods version 1.6.0.beta.1

[✓] Android Studio (version 3.2)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin version 29.1.1
    • Dart plugin version 181.5656
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1136-b06)

[✓] VS Code (version 1.30.0)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 2.21.1

[✓] Connected device (3 available)
    • SAMSUNG SM G920A • 03157df3c5558209                         • android-arm64 • Android 5.1.1 (API
      22)
    • Max's iPhone     • 65760f04a8cdf8dc55bf798b8cf0ab5cf488674c • ios           • iOS 12.1
    • iPhone XS        • 9CFC4B23-BE03-4DC9-B1CD-5E1226F5A183     • ios           • iOS 12.1 (simulator)
```