Update Launcher to use theme colors.

Instead of using hard-coded variants of colors, use the theme color
that corresponds (colorAccent, colorPrimary, etc).

Updated:
- "Search for more apps" text
- App info drop target hover color
- PageIndicatorDots
- All apps & widget scroll bar & scroll popup colors
- All apps section text color
- widget picker background color

TODO:
- widget picker header color

BUG: 28625102
Change-Id: I74b543ff71b8caef8cd950c8183ac84c759cb4d5

src/com/android/launcher3/BaseRecyclerViewFastScrollPopup.java

@@ -53,7 +53,7 @@ public class BaseRecyclerViewFastScrollPopup {
         mRes = res;
         mRv = rv;
         mBgOriginalSize = res.getDimensionPixelSize(R.dimen.container_fastscroll_popup_size);
-        mBg = res.getDrawable(R.drawable.container_fastscroll_popup_bg);
+        mBg = rv.getContext().getDrawable(R.drawable.container_fastscroll_popup_bg);
         mBg.setBounds(0, 0, mBgOriginalSize, mBgOriginalSize);
         mTextPaint = new Paint();
         mTextPaint.setColor(Color.WHITE);