Improve messaging for enhanced notifications

The message displayed in battery settings will now more accurately
reflect when an estimate is enhanced based on our updated
definition of what that means.

Test: robotests
Bug: 64833846
Change-Id: Id635d78d8f56d10253e22df2705af93f2693db70

src/com/android/settings/fuelgauge/Estimate.java

@@ -0,0 +1,12 @@
+package com.android.settings.fuelgauge;
+
+public class Estimate {
+
+  public final long estimateMillis;
+  public final boolean isBasedOnUsage;
+
+  public Estimate(long estimateMillis, boolean isBasedOnUsage) {
+    this.estimateMillis = estimateMillis;
+    this.isBasedOnUsage = isBasedOnUsage;
+  }
+}