Unify storage calculations.

Due to one calculation using longs and the other using doubles, there
were situations where the percentage was off-by-one between the two
places.

By changing both places to now use doubles to calculate percentages, the
numbers should be unified.

Change-Id: I4f4ed19326562e198273adc60a1593c7d1a6b6a7
Fixes: 37923610
Test: Manual

src/com/android/settings/deviceinfo/storage/StorageSummaryDonutPreference.java

@@ -39,6 +39,7 @@ import com.android.settings.R;
 import com.android.settings.overlay.FeatureFactory;
 import com.android.settings.widget.DonutView;
 
+import java.text.NumberFormat;
 import java.util.Locale;
 
 /**
@@ -46,7 +47,7 @@ import java.util.Locale;
  * on a given storage volume. It is visualized with a donut graphing the % used.
  */
 public class StorageSummaryDonutPreference extends Preference implements View.OnClickListener {
-    private int mPercent = -1;
+    private double mPercent = -1;
 
     public StorageSummaryDonutPreference(Context context) {
         this(context, null);
@@ -64,8 +65,7 @@ public class StorageSummaryDonutPreference extends Preference implements View.On
             return;
         }
 
-        mPercent = MathUtils.constrain((int) ((usedBytes * 100) / totalBytes),
-                (usedBytes > 0) ? 1 : 0, 100);
+        mPercent = usedBytes / (double) totalBytes;
     }
 
     @Override