Remove drop target button drawable padding if text isn't hidden

Test: manual
Fix: 194320733
Change-Id: I12adeaf37cee5a0fcf383641f24b7750f14daf27
diff --git a/src/com/android/launcher3/ButtonDropTarget.java b/src/com/android/launcher3/ButtonDropTarget.java
index 0d33b6f..468d490 100644
--- a/src/com/android/launcher3/ButtonDropTarget.java
+++ b/src/com/android/launcher3/ButtonDropTarget.java
@@ -66,6 +66,8 @@
     private final int mDragDistanceThreshold;
     /** The size of the drawable shown in the drop target. */
     private final int mDrawableSize;
+    /** The padding, in pixels, between the text and drawable. */
+    private final int mDrawablePadding;
 
     protected CharSequence mText;
     protected Drawable mDrawable;
@@ -85,6 +87,8 @@
         Resources resources = getResources();
         mDragDistanceThreshold = resources.getDimensionPixelSize(R.dimen.drag_distanceThreshold);
         mDrawableSize = resources.getDimensionPixelSize(R.dimen.drop_target_text_size);
+        mDrawablePadding = resources.getDimensionPixelSize(
+                R.dimen.drop_target_button_drawable_padding);
     }
 
     @Override
@@ -300,6 +304,8 @@
             mTextVisible = isVisible;
             setText(newText);
             setCompoundDrawablesRelative(mDrawable, null, null, null);
+            int drawablePadding = mTextVisible ? mDrawablePadding : 0;
+            setCompoundDrawablePadding(drawablePadding);
         }
     }