Remove support for function keys. (#8840)

Function keys don't work great on any platform we support:
* Mac doesn't have first-class function keys.
* On Ubuntu: F1 opens the system help and F10 opens the file dialog.
* ... and Windows is a mess as well.

packages/flutter_tools/lib/src/base/logger.dart

@@ -255,10 +255,6 @@ class AnsiTerminal {
     supportsColor = (term != null && term != 'dumb') || flutterAnsiTerm;
   }
 
-  static const String KEY_F1  = '\u001BOP';
-  static const String KEY_F5  = '\u001B[15~';
-  static const String KEY_F10 = '\u001B[21~';
-
   static const String _bold  = '\u001B[1m';
   static const String _reset = '\u001B[0m';
   static const String _clear = '\u001B[2J\u001B[H';

packages/flutter_tools/lib/src/resident_runner.dart

@@ -235,8 +235,8 @@ abstract class ResidentRunner {
 
     printStatus(''); // the key the user tapped might be on this line
 
-    if (lower == 'h' || lower == '?' || character == AnsiTerminal.KEY_F1) {
-      // F1, help
+    if (lower == 'h' || lower == '?') {
+      // help
       printHelp(details: true);
       return true;
     } else if (lower == 'w') {
@@ -265,8 +265,8 @@ abstract class ResidentRunner {
         print('Switched operating system to: $platform');
         return true;
       }
-    } else if (lower == 'q' || character == AnsiTerminal.KEY_F10) {
-      // F10, exit
+    } else if (lower == 'q') {
+      // exit
       await stop();
       return true;
     } else if (lower == 'd') {

packages/flutter_tools/lib/src/run_cold.dart

@@ -165,9 +165,9 @@ class ColdRunner extends ResidentRunner {
         printHelpDetails();
     }
     if (haveDetails && !details) {
-      printStatus('For a more detailed help message, press "h" or F1. To quit, press "q", F10, or Ctrl-C.');
+      printStatus('For a more detailed help message, press "h". To quit, press "q".');
     } else {
-      printStatus('To repeat this help message, press "h" or F1. To quit, press "q", F10, or Ctrl-C.');
+      printStatus('To repeat this help message, press "h". To quit, press "q".');
     }
   }
 

packages/flutter_tools/lib/src/run_hot.dart

@@ -230,7 +230,7 @@ class HotRunner extends ResidentRunner {
   @override
   Future<Null> handleTerminalCommand(String code) async {
     final String lower = code.toLowerCase();
-    if ((lower == 'r') || (code == AnsiTerminal.KEY_F5)) {
+    if (lower == 'r') {
       final OperationResult result = await restart(fullRestart: code == 'R');
       if (!result.isOk) {
         // TODO(johnmccutchan): Attempt to determine the number of errors that
@@ -511,16 +511,16 @@ class HotRunner extends ResidentRunner {
     const String bold = '\u001B[0;1m';
     const String reset = '\u001B[0m';
     printStatus(
-      '$fire  To hot reload your app on the fly, press "r" or F5. To restart the app entirely, press "R".',
+      '$fire  To hot reload your app on the fly, press "r". To restart the app entirely, press "R".',
       ansiAlternative: '$red$fire$bold  To hot reload your app on the fly, '
-                       'press "r" or F5. To restart the app entirely, press "R".$reset'
+                       'press "r". To restart the app entirely, press "R".$reset'
     );
     printStatus('The Observatory debugger and profiler is available at: $_observatoryUri');
     if (details) {
       printHelpDetails();
-      printStatus('To repeat this help message, press "h" or F1. To quit, press "q", F10, or Ctrl-C.');
+      printStatus('To repeat this help message, press "h". To quit, press "q".');
     } else {
-      printStatus('For a more detailed help message, press "h" or F1. To quit, press "q", F10, or Ctrl-C.');
+      printStatus('For a more detailed help message, press "h". To quit, press "q".');
     }
   }