Ensuring that we use the screen width more optimally in AllApps.

- Fixing issue with prediction bar height being calculated incorrectly
- Fixing issue where the prediction bar divider was not drawn exactly
  between the bar and the first row of apps
- Removing padding to allow scrollbars to reach full height

Bug: 20222023
Bug: 21335377
Change-Id: I2c0614a36e2294d0d6184a6bff4847876ffe971e

src/com/android/launcher3/Utilities.java

@@ -54,7 +54,6 @@ import android.util.SparseArray;
 import android.util.TypedValue;
 import android.view.View;
 import android.widget.Toast;
-
 import junit.framework.Assert;
 
 import java.io.ByteArrayOutputStream;
@@ -625,6 +624,16 @@ public final class Utilities {
         return m.replaceAll("$1");
     }
 
+    /**
+     * Calculates the height of a given string at a specific text size.
+     */
+    public static float calculateTextHeight(float textSizePx) {
+        Paint p = new Paint();
+        p.setTextSize(textSizePx);
+        Paint.FontMetrics fm = p.getFontMetrics();
+        return -fm.top + fm.bottom;
+    }
+
     @TargetApi(Build.VERSION_CODES.JELLY_BEAN_MR1)
     public static boolean isRtl(Resources res) {
         return (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) &&