delegate checkInputConnectionProxy to the relevant platform view (#9426)

The previous logic allowed proxying for any view that belonged to one of the platform views' virtual displays which may lead to us allowing proxying for a view that the platform view isn't allowing proxying for, previous logic also didn't account for unattached views.

This change instead delegates the decision to the platform view.

We use the fact that each virtual display has its unique context to associate any view with its relevant virtual display.

A nice side effect of calling the platform view's checkInputConnectionProxy for webviews is that the plugin now has a way to get a handle to the ThreadedInputConnectionProxyView, which may be useful for getting keyboard working on webview's prior to Android N.

shell/platform/android/io/flutter/plugin/platform/PlatformViewsController.java

@@ -19,19 +19,12 @@ import android.view.View;
 
 import io.flutter.embedding.engine.dart.DartExecutor;
 import io.flutter.embedding.engine.systemchannels.PlatformViewsChannel;
-import io.flutter.plugin.common.BinaryMessenger;
-import io.flutter.plugin.common.MethodCall;
-import io.flutter.plugin.common.MethodChannel;
-import io.flutter.plugin.common.StandardMethodCodec;
 import io.flutter.plugin.editing.TextInputPlugin;
 import io.flutter.view.AccessibilityBridge;
 import io.flutter.view.TextureRegistry;
 
-import java.lang.reflect.Method;
-import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.HashMap;
-import java.util.HashSet;
 import java.util.List;
 
 /**
@@ -64,10 +57,10 @@ public class PlatformViewsController implements PlatformViewsAccessibilityDelega
 
     private final HashMap<Integer, VirtualDisplayController> vdControllers;
 
-    // The set of root views for all active virtual displays managed by this controller.
-    // This allows an O(1) check whether a view is managed by this controller(by checking if it's root view is in this
-    // set). This is used by isPlatformView.
-    private final HashSet<View> vdRootViews;
+    // Maps a virtual display's context to the platform view hosted in this virtual display.
+    // Since each virtual display has it's unique context this allows associating any view with the platform view that
+    // it is associated with(e.g if a platform view creates other views in the same virtual display.
+    private final HashMap<Context, View> contextToPlatformView;
 
     private final PlatformViewsChannel.PlatformViewsHandler channelHandler = new PlatformViewsChannel.PlatformViewsHandler() {
         @TargetApi(Build.VERSION_CODES.JELLY_BEAN_MR1)
@@ -125,7 +118,7 @@ public class PlatformViewsController implements PlatformViewsAccessibilityDelega
             vdControllers.put(request.viewId, vdController);
             View platformView = vdController.getView();
             platformView.setLayoutDirection(request.direction);
-            vdRootViews.add(platformView.getRootView());
+            contextToPlatformView.put(platformView.getContext(), platformView);
 
             // TODO(amirh): copy accessibility nodes to the FlutterView's accessibility tree.
 
@@ -142,8 +135,7 @@ public class PlatformViewsController implements PlatformViewsAccessibilityDelega
                     + viewId);
             }
 
-            View rootView = vdController.getView().getRootView();
-            vdRootViews.remove(rootView);
+            contextToPlatformView.remove(vdController.getView().getContext());
 
             vdController.dispose();
             vdControllers.remove(viewId);
@@ -170,7 +162,6 @@ public class PlatformViewsController implements PlatformViewsAccessibilityDelega
                 // and unlock after the resize is complete.
                 textInputPlugin.lockPlatformViewInputConnection();
             }
-            vdRootViews.remove(vdController.getView().getRootView());
             vdController.resize(
                     physicalWidth,
                     physicalHeight,
@@ -184,7 +175,6 @@ public class PlatformViewsController implements PlatformViewsAccessibilityDelega
                         }
                     }
             );
-            vdRootViews.add(vdController.getView().getRootView());
         }
 
         @Override
@@ -264,7 +254,7 @@ public class PlatformViewsController implements PlatformViewsAccessibilityDelega
         registry = new PlatformViewRegistryImpl();
         vdControllers = new HashMap<>();
         accessibilityEventsDelegate = new AccessibilityEventsDelegate();
-        vdRootViews = new HashSet<>();
+        contextToPlatformView = new HashMap<>();
     }
 
     /**
@@ -335,10 +325,22 @@ public class PlatformViewsController implements PlatformViewsAccessibilityDelega
     }
 
     /**
-     * Returns true if the view is a platform view managed by this controller.
+     * Returns true if Flutter should perform input connection proxying for the view.
+     *
+     * If the view is a platform view managed by this platform views controller returns true.
+     * Else if the view was created in a platform view's VD, delegates the decision to the platform view's
+     * {@link View#checkInputConnectionProxy(View)} method.
+     * Else returns false.
      */
-    public boolean isPlatformView(View view) {
-        return vdRootViews.contains(view.getRootView());
+    public boolean checkInputConnectionProxy(View view) {
+        if(!contextToPlatformView.containsKey(view.getContext())) {
+            return false;
+        }
+        View platformView = contextToPlatformView.get(view.getContext());
+        if (platformView == view) {
+            return true;
+        }
+        return platformView.checkInputConnectionProxy(view);
     }
 
     public PlatformViewRegistry getRegistry() {

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

@@ -399,8 +399,7 @@ public class FlutterView extends SurfaceView implements BinaryMessenger, Texture
 
     @Override
     public boolean checkInputConnectionProxy(View view) {
-        PlatformViewsController platformViewsController = mNativeView.getPluginRegistry().getPlatformViewsController();
-        return platformViewsController.isPlatformView(view);
+        return mNativeView.getPluginRegistry().getPlatformViewsController().checkInputConnectionProxy(view);
     }
 
     @Override