Allow IME to show when control target differs from DC target

cause:
In this particular case, IME is requested by editor in the window,
but before IME could be drawn, app shows a new popupWindow on top.
This popupWindow has FLAG_ALT_FOCUSABLE_IM but it also has transparency.
So, for legacy reasons it becomes the IME target in DisplayContent and
IME will not be shown as Dc target and window requesting IME don't match.

solution:
Allow window requesting IME to show IME if it is same as control target
and current DC target has transparency.

Fix: 155662459
Test: atest ImeInsetsSourceProviderTest

Change-Id: I3540f4f23c449c50baff9981b58c36afff302455
diff --git a/services/core/java/com/android/server/wm/ImeInsetsSourceProvider.java b/services/core/java/com/android/server/wm/ImeInsetsSourceProvider.java
index 7491376..31a499a 100644
--- a/services/core/java/com/android/server/wm/ImeInsetsSourceProvider.java
+++ b/services/core/java/com/android/server/wm/ImeInsetsSourceProvider.java
@@ -18,9 +18,11 @@
 
 import static com.android.server.wm.ProtoLogGroup.WM_DEBUG_IME;
 
+import android.graphics.PixelFormat;
 import android.view.InsetsSource;
 import android.view.WindowInsets;
 
+import com.android.internal.annotations.VisibleForTesting;
 import com.android.server.protolog.common.ProtoLog;
 
 /**
@@ -100,7 +102,8 @@
         mShowImeRunner = null;
     }
 
-    private boolean isImeTargetFromDisplayContentAndImeSame() {
+    @VisibleForTesting
+    boolean isImeTargetFromDisplayContentAndImeSame() {
         // IMMS#mLastImeTargetWindow always considers focused window as
         // IME target, however DisplayContent#computeImeTarget() can compute
         // a different IME target.
@@ -111,6 +114,7 @@
         // TODO(b/139861270): Remove the child & sublayer check once IMMS is aware of
         //  actual IME target.
         final WindowState dcTarget = mDisplayContent.mInputMethodTarget;
+        final InsetsControlTarget controlTarget = mDisplayContent.mInputMethodControlTarget;
         if (dcTarget == null || mImeTargetFromIme == null) {
             return false;
         }
@@ -120,6 +124,9 @@
         return (!dcTarget.isClosing() && mImeTargetFromIme == dcTarget)
                 || (mImeTargetFromIme != null && dcTarget.getParentWindow() == mImeTargetFromIme
                         && dcTarget.mSubLayer > mImeTargetFromIme.mSubLayer)
-                || mImeTargetFromIme == mDisplayContent.getImeFallback();
+                || mImeTargetFromIme == mDisplayContent.getImeFallback()
+                // If IME target is transparent but control target matches requesting window.
+                || (controlTarget == mImeTargetFromIme
+                        && PixelFormat.formatHasAlpha(dcTarget.mAttrs.format));
     }
 }
diff --git a/services/tests/wmtests/src/com/android/server/wm/ImeInsetsSourceProviderTest.java b/services/tests/wmtests/src/com/android/server/wm/ImeInsetsSourceProviderTest.java
new file mode 100644
index 0000000..ca739c0
--- /dev/null
+++ b/services/tests/wmtests/src/com/android/server/wm/ImeInsetsSourceProviderTest.java
@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.server.wm;
+
+import static android.view.InsetsState.ITYPE_IME;
+import static android.view.WindowManager.LayoutParams.TYPE_APPLICATION;
+
+import static org.junit.Assert.assertTrue;
+
+import android.graphics.PixelFormat;
+import android.platform.test.annotations.Presubmit;
+import android.view.InsetsSource;
+
+import androidx.test.filters.SmallTest;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+@SmallTest
+@Presubmit
+@RunWith(WindowTestRunner.class)
+public class ImeInsetsSourceProviderTest extends WindowTestsBase {
+
+    private InsetsSource mImeSource = new InsetsSource(ITYPE_IME);
+    private ImeInsetsSourceProvider mImeProvider;
+
+    @Before
+    public void setUp() throws Exception {
+        mImeSource.setVisible(true);
+        mImeProvider = new ImeInsetsSourceProvider(mImeSource,
+                mDisplayContent.getInsetsStateController(), mDisplayContent);
+    }
+
+    @Test
+    public void testTransparentControlTargetWindowCanShowIme() {
+        final WindowState appWin = createWindow(null, TYPE_APPLICATION, "app");
+        final WindowState popup = createWindow(appWin, TYPE_APPLICATION, "popup");
+        mDisplayContent.mInputMethodControlTarget = popup;
+        mDisplayContent.mInputMethodTarget = appWin;
+        popup.mAttrs.format = PixelFormat.TRANSPARENT;
+        mImeProvider.scheduleShowImePostLayout(appWin);
+        assertTrue(mImeProvider.isImeTargetFromDisplayContentAndImeSame());
+    }
+}