Simplifying some launcher themes

> Replacing some colors with theme attributes
> Simplifying styles definition by removing unnecessary inheritance and inlining some definitions

Change-Id: Ifa167515cae6a7fd3720f1a52ff9ce11abb4495f
diff --git a/res/layout/all_apps_button.xml b/res/layout/all_apps_button.xml
index 68cc109..4bc780a 100644
--- a/res/layout/all_apps_button.xml
+++ b/res/layout/all_apps_button.xml
@@ -14,6 +14,4 @@
      limitations under the License.
 -->
 
-<TextView xmlns:android="http://schemas.android.com/apk/res/android"
-   style="@style/Icon"
-   android:focusable="true" />
+<TextView style="@style/BaseIcon" />