Data usage axis grow/shrink, other fixes.

When dragging vertical sweeps near edges, grow or shrink axis scale
to give users access to larger limits.  Triggers 10% for each 250ms
that user continues holding.  Change axis math to support arbitrary
ranges beyond [0,5GB].

Show "empty" message when no application details found.  Added strings
that didn't appear in default language.  Better sweep margins using
dip instead of scale units.  Format time ranges in local time instead
of UTC.  Only show dashed estimate when it would reach near warning
or limit.  Extend app usage series until "now" when buckets missing.

Bug: 5096685, 5092538, 5058158, 5058114, 5058024, 4643457
Change-Id: I45cf33f7f3baeba1bfa5b21f31cb0a12006f62fa

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

@@ -25,14 +25,26 @@ import android.text.SpannableStringBuilder;
  */
 public interface ChartAxis {
 
+    /** Set range of raw values this axis should cover. */
     public void setBounds(long min, long max);
+    /** Set range of screen points this axis should cover. */
     public void setSize(float size);
 
+    /** Convert raw value into screen point. */
     public float convertToPoint(long value);
+    /** Convert screen point into raw value. */
     public long convertToValue(float point);
 
+    /** Build label that describes given raw value. */
     public void buildLabel(Resources res, SpannableStringBuilder builder, long value);
 
+    /** Return list of tick points for drawing a grid. */
     public float[] getTickPoints();
 
+    /**
+     * Test if given raw value should cause the axis to grow or shrink;
+     * returning positive value to grow and negative to shrink.
+     */
+    public int shouldAdjustAxis(long value);
+
 }