Adjust homepage styles and layouts

- Fine tune the header text size and position
- Fix the header overlapping problem on the homepage and collapsing
  toolbar pages when configuration changes by adding android:id.
- New AppBarScrollingViewBehavior for the homepage to avoid manually
  offsetting the IA
- Correct the formula of counting search box height

Test: robotest, manual
Fixes: 177967923
Fixes: 177968564
Change-Id: Id3ed44f4296fa2a19d6890b009d3881a5c140bbd

tests/robotests/src/com/android/settings/homepage/SettingsHomepageActivityTest.java

@@ -26,7 +26,6 @@ import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
 import android.os.Build;
-import android.view.View;
 import android.view.Window;
 import android.view.WindowManager;
 import android.widget.FrameLayout;
@@ -54,32 +53,6 @@ public class SettingsHomepageActivityTest {
         MockitoAnnotations.initMocks(this);
     }
 
-    @Test
-    public void setDefaultHomepageContainerPaddingTop_shouldSetSearchBoxHeight() {
-        final SettingsHomepageActivity activity = Robolectric.buildActivity(
-                SettingsHomepageActivity.class).create().get();
-        final View view = activity.findViewById(R.id.homepage_container);
-
-        activity.setDefaultHomepageContainerPaddingTop();
-
-        final int actualPaddingTop = view.getPaddingTop();
-        assertThat(actualPaddingTop).isEqualTo(activity.getSearchBoxHeight());
-    }
-
-    @Test
-    public void setHomepageContainerTopOffset_shouldBeSetPaddingTop() {
-        final SettingsHomepageActivity activity = Robolectric.buildActivity(
-                SettingsHomepageActivity.class).create().get();
-        final View view = activity.findViewById(R.id.homepage_container);
-        final int offset = activity.getResources().getDimensionPixelSize(
-                R.dimen.suggestion_height);
-
-        activity.setHomepageContainerTopOffset(offset);
-
-        final int actualPaddingTop = view.getPaddingTop();
-        assertThat(actualPaddingTop).isEqualTo(activity.getSearchBoxHeight() + offset);
-    }
-
     @Test
     public void launch_shouldHaveAnimationForIaFragment() {
         final SettingsHomepageActivity activity = Robolectric.buildActivity(