diff --git a/packages/SystemUI/shared/Android.bp b/packages/SystemUI/shared/Android.bp
index f98a959..b2ae2a0 100644
--- a/packages/SystemUI/shared/Android.bp
+++ b/packages/SystemUI/shared/Android.bp
@@ -40,7 +40,8 @@
     name: "SystemUISharedLib",
     srcs: [
         "src/**/*.java",
-        "src/**/I*.aidl",
+        "src/**/*.kt",
+        "src/**/*.aidl",
         ":wm_shell-aidls",
     ],
 
diff --git a/packages/SystemUI/shared/src/com/android/systemui/shared/system/QuickStepContract.java b/packages/SystemUI/shared/src/com/android/systemui/shared/system/QuickStepContract.java
index 2cf3ad2..c468e41 100644
--- a/packages/SystemUI/shared/src/com/android/systemui/shared/system/QuickStepContract.java
+++ b/packages/SystemUI/shared/src/com/android/systemui/shared/system/QuickStepContract.java
@@ -36,6 +36,9 @@
  * Various shared constants between Launcher and SysUI as part of quickstep
  */
 public class QuickStepContract {
+    // Fully qualified name of the Launcher activity.
+    public static final String LAUNCHER_ACTIVITY_CLASS_NAME =
+            "com.google.android.apps.nexuslauncher.NexusLauncherActivity";
 
     public static final String KEY_EXTRA_SYSUI_PROXY = "extra_sysui_proxy";
     public static final String KEY_EXTRA_WINDOW_CORNER_RADIUS = "extra_window_corner_radius";
@@ -52,6 +55,8 @@
     // See IStartingWindow.aidl
     public static final String KEY_EXTRA_SHELL_STARTING_WINDOW =
             "extra_shell_starting_window";
+    // See ISmartspaceTransitionController.aidl
+    public static final String KEY_EXTRA_SMARTSPACE_TRANSITION_CONTROLLER = "smartspace_transition";
 
     public static final String NAV_BAR_MODE_2BUTTON_OVERLAY =
             WindowManagerPolicyConstants.NAV_BAR_MODE_2BUTTON_OVERLAY;
diff --git a/packages/SystemUI/shared/src/com/android/systemui/shared/system/smartspace/ISmartspaceCallback.aidl b/packages/SystemUI/shared/src/com/android/systemui/shared/system/smartspace/ISmartspaceCallback.aidl
new file mode 100644
index 0000000..511df4c
--- /dev/null
+++ b/packages/SystemUI/shared/src/com/android/systemui/shared/system/smartspace/ISmartspaceCallback.aidl
@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2021 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.systemui.shared.system.smartspace;
+
+import com.android.systemui.shared.system.smartspace.SmartspaceState;
+
+// Methods for getting and setting the state of a SmartSpace. This is used to allow a remote process
+// (such as System UI) to sync with and control a SmartSpace view hosted in another process (such as
+// Launcher).
+interface ISmartspaceCallback {
+
+    // Return information about the state of the SmartSpace, including location on-screen and
+    // currently selected page.
+    SmartspaceState getSmartspaceState();
+
+    // Set the currently selected page of this SmartSpace.
+    oneway void setSelectedPage(int selectedPage);
+
+    oneway void setVisibility(int visibility);
+}
\ No newline at end of file
diff --git a/packages/SystemUI/shared/src/com/android/systemui/shared/system/smartspace/ISmartspaceTransitionController.aidl b/packages/SystemUI/shared/src/com/android/systemui/shared/system/smartspace/ISmartspaceTransitionController.aidl
new file mode 100644
index 0000000..2b3e961
--- /dev/null
+++ b/packages/SystemUI/shared/src/com/android/systemui/shared/system/smartspace/ISmartspaceTransitionController.aidl
@@ -0,0 +1,24 @@
+/*
+ * Copyright (C) 2021 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.systemui.shared.system.smartspace;
+
+import com.android.systemui.shared.system.smartspace.ISmartspaceCallback;
+
+// Controller that keeps track of SmartSpace instances in remote processes (such as Launcher).
+interface ISmartspaceTransitionController {
+    oneway void setSmartspace(ISmartspaceCallback callback);
+}
\ No newline at end of file
diff --git a/packages/SystemUI/shared/src/com/android/systemui/shared/system/smartspace/SmartspaceState.aidl b/packages/SystemUI/shared/src/com/android/systemui/shared/system/smartspace/SmartspaceState.aidl
new file mode 100644
index 0000000..2d01d6a
--- /dev/null
+++ b/packages/SystemUI/shared/src/com/android/systemui/shared/system/smartspace/SmartspaceState.aidl
@@ -0,0 +1,21 @@
+/*
+ * Copyright (C) 2021 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.systemui.shared.system.smartspace;
+
+import com.android.systemui.shared.system.smartspace.SmartspaceState;
+
+parcelable SmartspaceState;
\ No newline at end of file
diff --git a/packages/SystemUI/shared/src/com/android/systemui/shared/system/smartspace/SmartspaceState.kt b/packages/SystemUI/shared/src/com/android/systemui/shared/system/smartspace/SmartspaceState.kt
new file mode 100644
index 0000000..2d51c4d
--- /dev/null
+++ b/packages/SystemUI/shared/src/com/android/systemui/shared/system/smartspace/SmartspaceState.kt
@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 2021 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.systemui.shared.system.smartspace
+
+import android.graphics.Rect
+import android.os.Parcel
+import android.os.Parcelable
+
+/**
+ * Represents the state of a SmartSpace, including its location on screen and the index of the
+ * currently selected page. This object contains all of the information needed to synchronize two
+ * SmartSpace instances so that we can perform shared-element transitions between them.
+ */
+class SmartspaceState() : Parcelable {
+    var boundsOnScreen: Rect = Rect()
+    var selectedPage = 0
+
+    constructor(parcel: Parcel) : this() {
+        this.boundsOnScreen = parcel.readParcelable(Rect::javaClass.javaClass.classLoader)
+        this.selectedPage = parcel.readInt()
+    }
+
+    override fun writeToParcel(dest: Parcel?, flags: Int) {
+        dest?.writeParcelable(boundsOnScreen, 0)
+        dest?.writeInt(selectedPage)
+    }
+
+    override fun describeContents(): Int {
+        return 0
+    }
+
+    override fun toString(): String {
+        return "boundsOnScreen: $boundsOnScreen, selectedPage: $selectedPage"
+    }
+
+    companion object CREATOR : Parcelable.Creator<SmartspaceState> {
+        override fun createFromParcel(parcel: Parcel): SmartspaceState {
+            return SmartspaceState(parcel)
+        }
+
+        override fun newArray(size: Int): Array<SmartspaceState?> {
+            return arrayOfNulls(size)
+        }
+    }
+}
\ No newline at end of file