Checkpoint of data usage UI, graphs and lists.

Chart of network usage over time, with draggable "sweep" bars for
inspection region and warning/limits.  Talks with NetworkStatsService
for live data, and updates list of application usage as inspection
region changes.

Change-Id: I2a406e6776daf7d74143c07ec683c10fe711c277

src/com/android/settings/widget/ChartAxis.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2011 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.settings.widget;
+
+/**
+ * Axis along a {@link ChartView} that knows how to convert between raw point
+ * and screen coordinate systems.
+ */
+public interface ChartAxis {
+
+    public void setSize(float size);
+
+    public float convertToPoint(long value);
+    public long convertToValue(float point);
+
+    public CharSequence getLabel(long value);
+
+    public float[] getTickPoints();
+
+}