Add PluginInflateContainer

PluginInflateContainer extends AutoReinflateContainer, except that
it also uses the plugin interface to allow the view to be swapped
out with something else.

Define an interface or abstract class as follows that includes the
version and action.

public interface MyInterface {
    public static final String ACTION =
            "com.android.systemui.action.PLUGIN_MYINTERFACE";

    public static final int VERSION = 1;

    void myImportantInterface();
}

Then put in a PluginInflateContainer to use and specify the interface
or class that will be implemented as viewType.  The layout specified
will be used by default and whenever a plugin is not present.

<com.android.systemui.PluginInflateContainer
    android:id="@+id/some_id"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout="@layout/my_default_component"
    systemui:viewType="com.android.systemui.plugins.MyInterface" />

Test: Manual
Change-Id: I2ef3fa8dbe344c4635df20056182c1c0b3846fdf
diff --git a/packages/SystemUI/src/com/android/systemui/PluginInflateContainer.java b/packages/SystemUI/src/com/android/systemui/PluginInflateContainer.java
new file mode 100644
index 0000000..efa7cae
--- /dev/null
+++ b/packages/SystemUI/src/com/android/systemui/PluginInflateContainer.java
@@ -0,0 +1,111 @@
+/*
+ * Copyright (C) 2016 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;
+
+import android.annotation.Nullable;
+import android.content.Context;
+import android.content.res.TypedArray;
+import android.util.AttributeSet;
+import android.util.Log;
+import android.view.View;
+
+import com.android.systemui.plugins.PluginListener;
+import com.android.systemui.plugins.PluginManager;
+import com.android.systemui.plugins.ViewProvider;
+
+/**
+ * Define an interface or abstract class as follows that includes the
+ * version and action.
+ *
+ * public interface MyInterface {
+ *     public static final String ACTION =
+ *             "com.android.systemui.action.PLUGIN_MYINTERFACE";
+ *
+ *     public static final int VERSION = 1;
+ *
+ *     void myImportantInterface();
+ * }
+ *
+ * Then put in a PluginInflateContainer to use and specify the interface
+ * or class that will be implemented as viewType.  The layout specified
+ * will be used by default and whenever a plugin is not present.
+ *
+ * <com.android.systemui.PluginInflateContainer
+ *     android:id="@+id/some_id"
+ *     android:layout_width="match_parent"
+ *     android:layout_height="match_parent"
+ *     android:layout="@layout/my_default_component"
+ *     systemui:viewType="com.android.systemui.plugins.MyInterface" />
+ */
+public class PluginInflateContainer extends AutoReinflateContainer
+        implements PluginListener<ViewProvider> {
+
+    private static final String TAG = "PluginInflateContainer";
+
+    private String mAction;
+    private int mVersion;
+    private View mPluginView;
+
+    public PluginInflateContainer(Context context, @Nullable AttributeSet attrs) {
+        super(context, attrs);
+        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.PluginInflateContainer);
+        String viewType = a.getString(R.styleable.PluginInflateContainer_viewType);
+        try {
+            Class c = Class.forName(viewType);
+            mAction = (String) c.getDeclaredField("ACTION").get(null);
+            mVersion = (int) c.getDeclaredField("VERSION").get(null);
+        } catch (Exception e) {
+            Log.d(TAG, "Problem getting class info " + viewType, e);
+            mAction = null;
+            mVersion = 0;
+        }
+    }
+
+    @Override
+    protected void onAttachedToWindow() {
+        super.onAttachedToWindow();
+        if (mAction != null) {
+            PluginManager.getInstance(getContext()).addPluginListener(mAction, this, mVersion);
+        }
+    }
+
+    @Override
+    protected void onDetachedFromWindow() {
+        super.onDetachedFromWindow();
+        if (mAction != null) {
+            PluginManager.getInstance(getContext()).removePluginListener(this);
+        }
+    }
+
+    @Override
+    protected void inflateLayoutImpl() {
+        if (mPluginView != null) {
+            addView(mPluginView);
+        } else {
+            super.inflateLayoutImpl();
+        }
+    }
+
+    @Override
+    public void onPluginConnected(ViewProvider plugin) {
+        mPluginView = plugin.getView();
+        inflateLayout();
+    }
+
+    @Override
+    public void onPluginDisconnected(ViewProvider plugin) {
+        mPluginView = null;
+        inflateLayout();
+    }
+}