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/BubbleTextView.java

@@ -103,7 +103,7 @@ public class BubbleTextView extends TextView
 
     public BubbleTextView(Context context, AttributeSet attrs, int defStyle) {
         super(context, attrs, defStyle);
-        mLauncher = (Launcher) context;
+        mLauncher = Launcher.getLauncher(context);
         DeviceProfile grid = mLauncher.getDeviceProfile();
 
         TypedArray a = context.obtainStyledAttributes(attrs,