Fix spelling errors in all the dartdocs. (#13061) I got tired of drive-by spelling fixes, so I figured I'd just take care of them all at once. This only corrects errors in the dartdocs, not regular comments, and I skipped any sample code in the dartdocs. It doesn't touch any identifiers in the dartdocs either. No code changes, just comments.

diff --git a/packages/flutter_tools/lib/src/base/file_system.dart b/packages/flutter_tools/lib/src/base/file_system.dart
index 556c8fe..296ecfe 100644
--- a/packages/flutter_tools/lib/src/base/file_system.dart
+++ b/packages/flutter_tools/lib/src/base/file_system.dart

@@ -140,7 +140,7 @@
 
 /// Canonicalizes [path].
 ///
-/// This function implements the behaviour of `canonicalize` from
+/// This function implements the behavior of `canonicalize` from
 /// `package:path`. However, unlike the original, it does not change the ASCII
 /// case of the path. Changing the case can break hot reload in some situations,
 /// for an example see: https://github.com/flutter/flutter/issues/9539.

diff --git a/packages/flutter_tools/lib/src/base/port_scanner.dart b/packages/flutter_tools/lib/src/base/port_scanner.dart
index 86cc401..e1c0a45 100644
--- a/packages/flutter_tools/lib/src/base/port_scanner.dart
+++ b/packages/flutter_tools/lib/src/base/port_scanner.dart

@@ -28,7 +28,7 @@
   /// Returns an available port as close to [defaultPort] as possible.
   ///
   /// If [defaultPort] is available, this will return it. Otherwise, it will
-  /// search for an avaiable port close to [defaultPort]. If it cannot find one,
+  /// search for an available port close to [defaultPort]. If it cannot find one,
   /// it will return any available port.
   Future<int> findPreferredPort(int defaultPort) async {
     int iterationCount = 0;

diff --git a/packages/flutter_tools/lib/src/base/terminal.dart b/packages/flutter_tools/lib/src/base/terminal.dart
index 842180e..5a64b55 100644
--- a/packages/flutter_tools/lib/src/base/terminal.dart
+++ b/packages/flutter_tools/lib/src/base/terminal.dart

@@ -89,7 +89,7 @@
     return _broadcastStdInString;
   }
 
-  /// Prompts the user to input a chraracter within the accepted list.
+  /// Prompts the user to input a character within the accepted list.
   /// Reprompts if inputted character is not in the list.
   ///
   /// `prompt` is the text displayed prior to waiting for user input each time.

diff --git a/packages/flutter_tools/lib/src/base/utils.dart b/packages/flutter_tools/lib/src/base/utils.dart
index 2a4fee1..cbe3507 100644
--- a/packages/flutter_tools/lib/src/base/utils.dart
+++ b/packages/flutter_tools/lib/src/base/utils.dart

@@ -184,15 +184,15 @@
 ///
 ///     f47ac10b-58cc-4372-a567-0e02b2c3d479
 ///
-/// The generated uuids are 128 bit numbers encoded in a specific string format.
+/// The generated UUIDs are 128 bit numbers encoded in a specific string format.
 ///
 /// For more information, see
 /// http://en.wikipedia.org/wiki/Universally_unique_identifier.
 class Uuid {
   final Random _random = new Random();
 
-  /// Generate a version 4 (random) uuid. This is a uuid scheme that only uses
-  /// random numbers as the source of the generated uuid.
+  /// Generate a version 4 (random) UUID. This is a UUID scheme that only uses
+  /// random numbers as the source of the generated UUID.
   String generateV4() {
     // Generate xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx / 8-4-4-4-12.
     final int special = 8 + _random.nextInt(4);

diff --git a/packages/flutter_tools/lib/src/device.dart b/packages/flutter_tools/lib/src/device.dart
index dc85b43..e79c73f 100644
--- a/packages/flutter_tools/lib/src/device.dart
+++ b/packages/flutter_tools/lib/src/device.dart

@@ -389,7 +389,7 @@
   @override
   String toString() => name;
 
-  /// Process ID of the app on the deivce.
+  /// Process ID of the app on the device.
   int appPid;
 }
 

diff --git a/packages/flutter_tools/lib/src/ios/mac.dart b/packages/flutter_tools/lib/src/ios/mac.dart
index 644f66a..ee60c27 100644
--- a/packages/flutter_tools/lib/src/ios/mac.dart
+++ b/packages/flutter_tools/lib/src/ios/mac.dart

@@ -95,7 +95,7 @@
   /// Starts `idevicesyslog` and returns the running process.
   Future<Process> startLogger() => runCommand(<String>['idevicesyslog']);
 
-  /// Captures a screenshot to the specified outputfile.
+  /// Captures a screenshot to the specified outputFile.
   Future<Null> takeScreenshot(File outputFile) {
     return runCheckedAsync(<String>['idevicescreenshot', outputFile.path]);
   }

diff --git a/packages/flutter_tools/lib/src/runner/flutter_command.dart b/packages/flutter_tools/lib/src/runner/flutter_command.dart
index 025a8be..a61beed 100644
--- a/packages/flutter_tools/lib/src/runner/flutter_command.dart
+++ b/packages/flutter_tools/lib/src/runner/flutter_command.dart

@@ -50,7 +50,7 @@
   /// latency without measuring user interaction time.
   ///
   /// [FlutterCommand] will automatically measure and report the command's
-  /// complete time if not overriden.
+  /// complete time if not overridden.
   final DateTime endTimeOverride;
 }
 

diff --git a/packages/flutter_tools/lib/src/vmservice.dart b/packages/flutter_tools/lib/src/vmservice.dart
index 703caf3..f0d4f15 100644
--- a/packages/flutter_tools/lib/src/vmservice.dart
+++ b/packages/flutter_tools/lib/src/vmservice.dart

@@ -533,7 +533,7 @@
 }
 
 /// A ServiceObjectOwner is either a [VM] or an [Isolate]. Owners can cache
-/// and/or canonicalize service objets received over the wire.
+/// and/or canonicalize service objects received over the wire.
 abstract class ServiceObjectOwner extends ServiceObject {
   ServiceObjectOwner._empty(ServiceObjectOwner owner) : super._empty(owner);