Display a message if hardware rendering is supported (#15266)

* add device.supportsHardwareRendering and display a message if true

* Address some comments

packages/flutter_tools/lib/src/commands/run.dart

@@ -284,9 +284,27 @@ class RunCommand extends RunCommandBase {
     }
 
     for (Device device in devices) {
-      if (await device.isLocalEmulator && !isEmulatorBuildMode(getBuildMode()))
+      if (await device.isLocalEmulator) {
+        if (await device.supportsHardwareRendering) {
+          final bool enableSoftwareRendering = argResults['enable-software-rendering'] == true;
+          if (enableSoftwareRendering) {
+            printStatus(
+              'Using software rendering with device ${device.name}. You may get better performance'
+              'with hardware mode by configuring hardware rendering for your device.'
+            );
+          } else {
+            printStatus(
+              'Using hardware rendering with device ${device.name}. If you get graphics artifacts,'
+              'consider enabling software rendering with "--enable-software-rendering".'
+            );
+          }
+        }
+
+        if (!isEmulatorBuildMode(getBuildMode())) {
           throwToolExit('${toTitleCase(getModeName(getBuildMode()))} mode is not supported for emulators.');
         }
+      }
+    }
 
     if (hotMode) {
       for (Device device in devices) {

packages/flutter_tools/lib/src/device.dart

@@ -192,6 +192,25 @@ abstract class Device {
   /// Whether it is an emulated device running on localhost.
   Future<bool> get isLocalEmulator;
 
+  /// Whether the device is a simulator on a platform which supports hardware rendering.
+  Future<bool> get supportsHardwareRendering async {
+    assert(await isLocalEmulator);
+    switch (await targetPlatform) {
+      case TargetPlatform.android_arm:
+      case TargetPlatform.android_arm64:
+      case TargetPlatform.android_x64:
+      case TargetPlatform.android_x86:
+        return true;
+      case TargetPlatform.ios:
+      case TargetPlatform.darwin_x64:
+      case TargetPlatform.linux_x64:
+      case TargetPlatform.windows_x64:
+      case TargetPlatform.fuchsia:
+      default:
+        return false;
+    }
+  }
+
   /// Check if a version of the given app is already installed
   Future<bool> isAppInstalled(ApplicationPackage app);