Refactoring all apps search to support external search bar.

- Adding support for an external search bar that can be used
  to search a container view.  This adds a new interface
  AllAppsSearchController which manages the external search
  bar.  Each controller will have its own search implementation
  which means that we no longer need a common AppSearchManager
  interface.
- Removing elevation controller as we no longer have a builtin
  search bar in all apps
- Refactoring container view insets so that they behave
  the same in all containers.
- Refactoring apps view to ensure that we only update the number
  of columns with the available width
- Cleaning up LauncherCallbacks interface

Bug: 20127840
Bug: 21494973

Change-Id: I710b8e18196961d77d8a29f0c345531d480936fe

src/com/android/launcher3/BaseRecyclerView.java

@@ -89,9 +89,7 @@ public class BaseRecyclerView extends RecyclerView
     private int mLastY;
     private int mScrollbarWidth;
     private int mScrollbarInset;
-    private Rect mBackgroundPadding = new Rect();
-
-
+    protected Rect mBackgroundPadding = new Rect();
 
     public BaseRecyclerView(Context context) {
         this(context, null);
@@ -230,6 +228,10 @@ public class BaseRecyclerView extends RecyclerView
         return false;
     }
 
+    public void updateBackgroundPadding(Rect padding) {
+        mBackgroundPadding.set(padding);
+    }
+
     @Override
     protected void dispatchDraw(Canvas canvas) {
         super.dispatchDraw(canvas);
@@ -340,9 +342,10 @@ public class BaseRecyclerView extends RecyclerView
             // Calculate the position for the fast scroller popup
             Rect bgBounds = mFastScrollerBg.getBounds();
             if (Utilities.isRtl(getResources())) {
-                x = mBackgroundPadding.left + getScrollBarSize();
+                x = mBackgroundPadding.left + (2 * getScrollbarWidth());
             } else {
-                x = getWidth() - getPaddingRight() - getScrollBarSize() - bgBounds.width();
+                x = getWidth() - mBackgroundPadding.right - (2 * getScrollbarWidth()) -
+                        bgBounds.width();
             }
             y = mLastY - (int) (FAST_SCROLL_OVERLAY_Y_OFFSET_FACTOR * bgBounds.height());
             y = Math.max(getPaddingTop(), Math.min(y, getHeight() - getPaddingBottom() -