Introduce ThreadedInputConnection behind a switch

content/public/android/java/src/org/chromium/content/browser/input/ThreadedInputConnectionProxyView.java

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.content.browser.input;
+
+import android.content.Context;
+import android.os.Handler;
+import android.os.IBinder;
+import android.view.View;
+import android.view.inputmethod.EditorInfo;
+import android.view.inputmethod.InputConnection;
+
+import org.chromium.base.Log;
+import org.chromium.base.ThreadUtils;
+
+import java.util.concurrent.Callable;
+
+/**
+ * This is a fake View that is only exposed to InputMethodManager.
+ */
+public class ThreadedInputConnectionProxyView extends View {
+    private static final String TAG = "cr_Ime";
+    private static final boolean DEBUG_LOGS = false;
+
+    private final Handler mHandler;
+    private final View mContainerView;
+
+    ThreadedInputConnectionProxyView(Context context, Handler handler, View containerView) {
+        super(context);
+        mHandler = handler;
+        mContainerView = containerView;
+        setFocusable(true);
+        setFocusableInTouchMode(true);
+        setVisibility(View.VISIBLE);
+        if (DEBUG_LOGS) Log.w(TAG, "constructor");
+    }
+
+    @Override
+    public Handler getHandler() {
+        if (DEBUG_LOGS) Log.w(TAG, "getHandler");
+        return mHandler;
+    }
+
+    @Override
+    public boolean checkInputConnectionProxy(View view) {
+        if (DEBUG_LOGS) Log.w(TAG, "checkInputConnectionProxy");
+        return mContainerView == view;
+    }
+
+    @Override
+    public InputConnection onCreateInputConnection(final EditorInfo outAttrs) {
+        if (DEBUG_LOGS) Log.w(TAG, "onCreateInputConnection");
+        return ThreadUtils.runOnUiThreadBlockingNoException(new Callable<InputConnection>() {
+            @Override
+            public InputConnection call() throws Exception {
+                return mContainerView.onCreateInputConnection(outAttrs);

[aelias_OOO_until_Jul13, 2016/02/24 00:58:57]

I think the weird stack trace examination in
shouldTriggerDelayedOnCreateInputConnection could be avoided by calling a
non-public method from here instead of View.onCreateInputConnection.  How about
passing in a reference to the ThreadedInputConnectionFactory in this class's
constructor and then calling a method directly on that called something like
"createInputConnectionForProxyView()"

[Changwan Ryu, 2016/02/24 01:46:31]

Unfortunately, there are apps that override webview and even
onCreateInputConnection.
https://crbug.com/584426 and https://crbug.com/571229 are such examples.

I hope that we can still call those overridden methods. Otherwise, they will
think that onCreateInputConnection() always returns null, and there may be some
side effect. With the current implementation they will just think that input
method got restarted.

[aelias_OOO_until_Jul13, 2016/02/24 02:09:14]

Ah right, sorry about that, I already had forgotten the discussion we just had
last week.  Please add a comment mentioning this use case so I don't forget
again :).

Also, could you manually test those two apps mentioned in the bugs and make sure
they're happy with ThreadedInputConnection, if you haven't already?

+            }
+        });
+    }
+
+    @Override
+    public boolean hasFocus() {
+        if (DEBUG_LOGS) Log.w(TAG, "hasFocus");
+        return ThreadUtils.runOnUiThreadBlockingNoException(new Callable<Boolean>() {
+            @Override
+            public Boolean call() throws Exception {
+                return mContainerView.hasFocus();
+            }
+        });
+    }
+
+    @Override
+    public boolean hasWindowFocus() {
+        if (DEBUG_LOGS) Log.w(TAG, "hasWindowFocus");
+        return ThreadUtils.runOnUiThreadBlockingNoException(new Callable<Boolean>() {
+            @Override
+            public Boolean call() throws Exception {
+                return mContainerView.hasWindowFocus();
+            }
+        });
+    }
+
+    @Override
+    public View getRootView() {
+        if (DEBUG_LOGS) Log.w(TAG, "getRootView");
+        return ThreadUtils.runOnUiThreadBlockingNoException(new Callable<View>() {
+            @Override
+            public View call() throws Exception {
+                return mContainerView.getRootView();
+            }
+        });
+    }
+
+    @Override
+    public boolean onCheckIsTextEditor() {
+        if (DEBUG_LOGS) Log.w(TAG, "onCheckIsTextEditor");
+        return ThreadUtils.runOnUiThreadBlockingNoException(new Callable<Boolean>() {
+            @Override
+            public Boolean call() throws Exception {
+                return mContainerView.onCheckIsTextEditor();
+            }
+        });
+    }
+
+    @Override
+    public boolean isFocused() {
+        if (DEBUG_LOGS) Log.w(TAG, "isFocused");
+        return ThreadUtils.runOnUiThreadBlockingNoException(new Callable<Boolean>() {
+            @Override
+            public Boolean call() throws Exception {
+                return mContainerView.isFocused();
+            }
+        });
+    }
+
+    @Override
+    public IBinder getWindowToken() {
+        if (DEBUG_LOGS) Log.w(TAG, "getWindowToken");
+        return ThreadUtils.runOnUiThreadBlockingNoException(new Callable<IBinder>() {
+            @Override
+            public IBinder call() throws Exception {
+                return mContainerView.getWindowToken();
+            }
+        });
+    }
+
+    @Override
+    public void onWindowFocusChanged(boolean hasWindowFocus) {
+        if (DEBUG_LOGS) Log.w(TAG, "onWindowFocusChanged:" + hasWindowFocus);
+        super.onWindowFocusChanged(hasWindowFocus);
+    }
+}