Fix lint errors to prepare for building Android files in Google (#5440)

shell/platform/android/io/flutter/app/FlutterActivityDelegate.java

@@ -205,7 +205,7 @@ public final class FlutterActivityDelegate
         Application app = (Application) activity.getApplicationContext();
         if (app instanceof FlutterApplication) {
             FlutterApplication flutterApp = (FlutterApplication) app;
-            if (this.equals(flutterApp.getCurrentActivity())) {
+            if (activity.equals(flutterApp.getCurrentActivity())) {
                 Log.i(TAG, "onPause setting current activity to null");
                 flutterApp.setCurrentActivity(null);
             }
@@ -251,7 +251,7 @@ public final class FlutterActivityDelegate
         Application app = (Application) activity.getApplicationContext();
         if (app instanceof FlutterApplication) {
             FlutterApplication flutterApp = (FlutterApplication) app;
-            if (this.equals(flutterApp.getCurrentActivity())) {
+            if (activity.equals(flutterApp.getCurrentActivity())) {
                 Log.i(TAG, "onDestroy setting current activity to null");
                 flutterApp.setCurrentActivity(null);
             }

shell/platform/android/io/flutter/plugin/common/StandardMethodCodec.java

@@ -84,6 +84,7 @@ public final class StandardMethodCodec implements MethodCodec {
                     return result;
                 }
             }
+            // Falls through intentionally.
             case 1: {
                 final Object code = messageCodec.readValue(envelope);
                 final Object message = messageCodec.readValue(envelope);

shell/platform/android/io/flutter/plugin/editing/InputConnectionAdaptor.java

@@ -91,8 +91,7 @@ class InputConnectionAdaptor extends BaseInputConnection {
 
     @Override
     public boolean deleteSurroundingText(int beforeLength, int afterLength) {
-        if (Selection.getSelectionStart(mEditable) == -1 ||
-            Selection.getSelectionStart(mEditable) == -1)
+        if (Selection.getSelectionStart(mEditable) == -1)
             return true;
 
         boolean result = super.deleteSurroundingText(beforeLength, afterLength);

shell/platform/android/io/flutter/view/AccessibilityBridge.java

@@ -424,6 +424,7 @@ class AccessibilityBridge extends AccessibilityNodeProvider implements BasicMess
                 if (mInputFocusedObject != null)
                     return createAccessibilityNodeInfo(mInputFocusedObject.id);
             }
+            // Fall through to check FOCUS_ACCESSIBILITY
             case AccessibilityNodeInfo.FOCUS_ACCESSIBILITY: {
                 if (mA11yFocusedObject != null)
                     return createAccessibilityNodeInfo(mA11yFocusedObject.id);