Pay off some technical debt. (#8710)

* Rename `Device.platform` to `Device.targetPlatform` to avoid
  collision with the exported variable from `platform.dart`
diff --git a/packages/flutter_tools/lib/src/android/android_device.dart b/packages/flutter_tools/lib/src/android/android_device.dart
index 5982a4b..be41523 100644
--- a/packages/flutter_tools/lib/src/android/android_device.dart
+++ b/packages/flutter_tools/lib/src/android/android_device.dart
@@ -89,7 +89,7 @@
   }
 
   @override
-  TargetPlatform get platform {
+  TargetPlatform get targetPlatform {
     if (_platform == null) {
       // http://developer.android.com/ndk/guides/abis.html (x86, armeabi-v7a, ...)
       switch (_getProperty('ro.product.cpu.abi')) {
@@ -278,14 +278,14 @@
     if (!_checkForSupportedAdbVersion() || !_checkForSupportedAndroidVersion())
       return new LaunchResult.failed();
 
-    if (platform != TargetPlatform.android_arm && mode != BuildMode.debug) {
+    if (targetPlatform != TargetPlatform.android_arm && mode != BuildMode.debug) {
       printError('Profile and release builds are only supported on ARM targets.');
       return new LaunchResult.failed();
     }
 
     if (!prebuiltApplication) {
       printTrace('Building APK');
-      await buildApk(platform,
+      await buildApk(targetPlatform,
           target: mainPath,
           buildMode: debuggingOptions.buildMode,
           kernelContent: kernelContent,
diff --git a/packages/flutter_tools/lib/src/commands/daemon.dart b/packages/flutter_tools/lib/src/commands/daemon.dart
index ff72a23..e83761c 100644
--- a/packages/flutter_tools/lib/src/commands/daemon.dart
+++ b/packages/flutter_tools/lib/src/commands/daemon.dart
@@ -647,7 +647,7 @@
   return <String, dynamic>{
     'id': device.id,
     'name': device.name,
-    'platform': getNameForTargetPlatform(device.platform),
+    'platform': getNameForTargetPlatform(device.targetPlatform),
     'emulator': device.isLocalEmulator
   };
 }
diff --git a/packages/flutter_tools/lib/src/commands/drive.dart b/packages/flutter_tools/lib/src/commands/drive.dart
index 0039474..6c93759 100644
--- a/packages/flutter_tools/lib/src/commands/drive.dart
+++ b/packages/flutter_tools/lib/src/commands/drive.dart
@@ -262,7 +262,7 @@
 
   printTrace('Installing application package.');
   final ApplicationPackage package = command.applicationPackages
-      .getPackageForPlatform(command.device.platform);
+      .getPackageForPlatform(command.device.targetPlatform);
   if (command.device.isAppInstalled(package))
     command.device.uninstallApp(package);
   command.device.installApp(package);
@@ -335,7 +335,7 @@
 
 Future<bool> _stopApp(DriveCommand command) async {
   printTrace('Stopping application.');
-  final ApplicationPackage package = command.applicationPackages.getPackageForPlatform(command.device.platform);
+  final ApplicationPackage package = command.applicationPackages.getPackageForPlatform(command.device.targetPlatform);
   final bool stopped = await command.device.stopApp(package);
   await command._deviceLogSubscription?.cancel();
   return stopped;
diff --git a/packages/flutter_tools/lib/src/commands/install.dart b/packages/flutter_tools/lib/src/commands/install.dart
index acfac12..30e71d4 100644
--- a/packages/flutter_tools/lib/src/commands/install.dart
+++ b/packages/flutter_tools/lib/src/commands/install.dart
@@ -31,7 +31,7 @@
 
   @override
   Future<Null> runCommand() async {
-    final ApplicationPackage package = applicationPackages.getPackageForPlatform(device.platform);
+    final ApplicationPackage package = applicationPackages.getPackageForPlatform(device.targetPlatform);
 
     Cache.releaseLockEarly();
 
diff --git a/packages/flutter_tools/lib/src/commands/run.dart b/packages/flutter_tools/lib/src/commands/run.dart
index 59f47ee..e159780 100644
--- a/packages/flutter_tools/lib/src/commands/run.dart
+++ b/packages/flutter_tools/lib/src/commands/run.dart
@@ -151,7 +151,7 @@
       return command;
 
     // Return 'run/ios'.
-    return '$command/${getNameForTargetPlatform(device.platform)}';
+    return '$command/${getNameForTargetPlatform(device.targetPlatform)}';
   }
 
   @override
diff --git a/packages/flutter_tools/lib/src/commands/stop.dart b/packages/flutter_tools/lib/src/commands/stop.dart
index 6d31775..c506ee2 100644
--- a/packages/flutter_tools/lib/src/commands/stop.dart
+++ b/packages/flutter_tools/lib/src/commands/stop.dart
@@ -31,9 +31,9 @@
 
   @override
   Future<Null> runCommand() async {
-    final ApplicationPackage app = applicationPackages.getPackageForPlatform(device.platform);
+    final ApplicationPackage app = applicationPackages.getPackageForPlatform(device.targetPlatform);
     if (app == null) {
-      final String platformName = getNameForTargetPlatform(device.platform);
+      final String platformName = getNameForTargetPlatform(device.targetPlatform);
       throwToolExit('No Flutter application for $platformName found in the current directory.');
     }
     printStatus('Stopping apps on ${device.name}.');
diff --git a/packages/flutter_tools/lib/src/device.dart b/packages/flutter_tools/lib/src/device.dart
index 09d3ab2..6d8711e 100644
--- a/packages/flutter_tools/lib/src/device.dart
+++ b/packages/flutter_tools/lib/src/device.dart
@@ -167,9 +167,7 @@
   // supported by Flutter, and, if not, why.
   String supportMessage() => isSupported() ? "Supported" : "Unsupported";
 
-  // TODO(tvolkert): Rename to `targetPlatform`, and remove the "as p"
-  // aliases on the `platform.dart` imports where applicable.
-  TargetPlatform get platform;
+  TargetPlatform get targetPlatform;
 
   String get sdkNameAndVersion;
 
@@ -254,13 +252,13 @@
     for (Device device in devices) {
       String supportIndicator = device.isSupported() ? '' : ' (unsupported)';
       if (device.isLocalEmulator) {
-        final String type = device.platform == TargetPlatform.ios ? 'simulator' : 'emulator';
+        final String type = device.targetPlatform == TargetPlatform.ios ? 'simulator' : 'emulator';
         supportIndicator += ' ($type)';
       }
       table.add(<String>[
         device.name,
         device.id,
-        '${getNameForTargetPlatform(device.platform)}',
+        '${getNameForTargetPlatform(device.targetPlatform)}',
         '${device.sdkNameAndVersion}$supportIndicator',
       ]);
     }
diff --git a/packages/flutter_tools/lib/src/ios/devices.dart b/packages/flutter_tools/lib/src/ios/devices.dart
index f9e274d..bbecfc5 100644
--- a/packages/flutter_tools/lib/src/ios/devices.dart
+++ b/packages/flutter_tools/lib/src/ios/devices.dart
@@ -9,7 +9,7 @@
 import '../base/file_system.dart';
 import '../base/io.dart';
 import '../base/os.dart';
-import '../base/platform.dart' as p;
+import '../base/platform.dart';
 import '../base/process.dart';
 import '../base/process_manager.dart';
 import '../build_info.dart';
@@ -31,7 +31,7 @@
   IOSDevices() : super('IOSDevices');
 
   @override
-  bool get supportsPlatform => p.platform.isMacOS;
+  bool get supportsPlatform => platform.isMacOS;
 
   @override
   List<Device> pollingGetDevices() => IOSDevice.getAttachedDevices();
@@ -129,7 +129,7 @@
     try {
       command = runCheckedSync(<String>['which', command]).trim();
     } catch (e) {
-      if (p.platform.isMacOS) {
+      if (platform.isMacOS) {
         printError('$command not found. $macInstructions');
       } else {
         printError('Cannot control iOS devices or simulators. $command is not available on your platform.');
@@ -323,7 +323,7 @@
   }
 
   Future<bool> pushFile(ApplicationPackage app, String localFile, String targetFile) async {
-    if (p.platform.isMacOS) {
+    if (platform.isMacOS) {
       runSync(<String>[
         pusherPath,
         '-t',
@@ -342,7 +342,7 @@
   }
 
   @override
-  TargetPlatform get platform => TargetPlatform.ios;
+  TargetPlatform get targetPlatform => TargetPlatform.ios;
 
   @override
   String get sdkNameAndVersion => 'iOS $_sdkVersion ($_buildVersion)';
diff --git a/packages/flutter_tools/lib/src/ios/simulators.dart b/packages/flutter_tools/lib/src/ios/simulators.dart
index 71b46c4..7631315 100644
--- a/packages/flutter_tools/lib/src/ios/simulators.dart
+++ b/packages/flutter_tools/lib/src/ios/simulators.dart
@@ -11,7 +11,7 @@
 import '../base/context.dart';
 import '../base/file_system.dart';
 import '../base/io.dart';
-import '../base/platform.dart' as p;
+import '../base/platform.dart';
 import '../base/process.dart';
 import '../base/process_manager.dart';
 import '../build_info.dart';
@@ -31,7 +31,7 @@
   IOSSimulators() : super('IOSSimulators');
 
   @override
-  bool get supportsPlatform => p.platform.isMacOS;
+  bool get supportsPlatform => platform.isMacOS;
 
   @override
   List<Device> pollingGetDevices() => IOSSimulatorUtils.instance.getAttachedDevices();
@@ -366,7 +366,7 @@
 
   @override
   bool isSupported() {
-    if (!p.platform.isMacOS) {
+    if (!platform.isMacOS) {
       _supportMessage = 'iOS devices require a Mac host machine.';
       return false;
     }
@@ -541,7 +541,7 @@
 
   Future<bool> pushFile(
       ApplicationPackage app, String localFile, String targetFile) async {
-    if (p.platform.isMacOS) {
+    if (platform.isMacOS) {
       final String simulatorHomeDirectory = _getSimulatorAppHomeDirectory(app);
       runCheckedSync(<String>['cp', localFile, fs.path.join(simulatorHomeDirectory, targetFile)]);
       return true;
@@ -554,7 +554,7 @@
   }
 
   @override
-  TargetPlatform get platform => TargetPlatform.ios;
+  TargetPlatform get targetPlatform => TargetPlatform.ios;
 
   @override
   String get sdkNameAndVersion => category;
diff --git a/packages/flutter_tools/lib/src/run_cold.dart b/packages/flutter_tools/lib/src/run_cold.dart
index 6979555..3a88b19 100644
--- a/packages/flutter_tools/lib/src/run_cold.dart
+++ b/packages/flutter_tools/lib/src/run_cold.dart
@@ -79,11 +79,11 @@
       }
     }
 
-    package = getApplicationPackageForPlatform(device.platform, applicationBinary: applicationBinary);
+    package = getApplicationPackageForPlatform(device.targetPlatform, applicationBinary: applicationBinary);
 
     if (package == null) {
-      String message = 'No application found for ${device.platform}.';
-      final String hint = getMissingPackageHintForPlatform(device.platform);
+      String message = 'No application found for ${device.targetPlatform}.';
+      final String hint = getMissingPackageHintForPlatform(device.targetPlatform);
       if (hint != null)
         message += '\n$hint';
       printError(message);
diff --git a/packages/flutter_tools/lib/src/run_hot.dart b/packages/flutter_tools/lib/src/run_hot.dart
index 7473c6f..9ea3400 100644
--- a/packages/flutter_tools/lib/src/run_hot.dart
+++ b/packages/flutter_tools/lib/src/run_hot.dart
@@ -124,11 +124,11 @@
       return 1;
     }
 
-    package = getApplicationPackageForPlatform(device.platform, applicationBinary: applicationBinary);
+    package = getApplicationPackageForPlatform(device.targetPlatform, applicationBinary: applicationBinary);
 
     if (package == null) {
-      String message = 'No application found for ${device.platform}.';
-      final String hint = getMissingPackageHintForPlatform(device.platform);
+      String message = 'No application found for ${device.targetPlatform}.';
+      final String hint = getMissingPackageHintForPlatform(device.targetPlatform);
       if (hint != null)
         message += '\n$hint';
       printError(message);
diff --git a/packages/flutter_tools/lib/src/runner/flutter_command.dart b/packages/flutter_tools/lib/src/runner/flutter_command.dart
index 3c7c92d..c1e8104 100644
--- a/packages/flutter_tools/lib/src/runner/flutter_command.dart
+++ b/packages/flutter_tools/lib/src/runner/flutter_command.dart
@@ -176,7 +176,7 @@
     devices = devices.where((Device device) => device.isSupported()).toList();
 
     if (androidOnly)
-      devices = devices.where((Device device) => device.platform == TargetPlatform.android_arm).toList();
+      devices = devices.where((Device device) => device.targetPlatform == TargetPlatform.android_arm).toList();
 
     if (devices.isEmpty) {
       printStatus('No supported devices connected.');
diff --git a/packages/flutter_tools/test/src/mocks.dart b/packages/flutter_tools/test/src/mocks.dart
index a8c83df..73ee9d8 100644
--- a/packages/flutter_tools/test/src/mocks.dart
+++ b/packages/flutter_tools/test/src/mocks.dart
@@ -31,7 +31,7 @@
 
 class MockAndroidDevice extends Mock implements AndroidDevice {
   @override
-  TargetPlatform get platform => TargetPlatform.android_arm;
+  TargetPlatform get targetPlatform => TargetPlatform.android_arm;
 
   @override
   bool isSupported() => true;
@@ -39,7 +39,7 @@
 
 class MockIOSDevice extends Mock implements IOSDevice {
   @override
-  TargetPlatform get platform => TargetPlatform.ios;
+  TargetPlatform get targetPlatform => TargetPlatform.ios;
 
   @override
   bool isSupported() => true;
@@ -47,7 +47,7 @@
 
 class MockIOSSimulator extends Mock implements IOSSimulator {
   @override
-  TargetPlatform get platform => TargetPlatform.ios;
+  TargetPlatform get targetPlatform => TargetPlatform.ios;
 
   @override
   bool isSupported() => true;