Merge AOSP android-9.0.0_r3

Fix conflicts and make it build in 5.1, 6.0, 7.1, 8.1, and 9.0

Change-Id: Ida0a64c29ff27d339b7f42a18d820930964ac6e4
diff --git a/gui/slidervalue.cpp b/gui/slidervalue.cpp
index 6f007e2..3aaffcc 100644
--- a/gui/slidervalue.cpp
+++ b/gui/slidervalue.cpp
@@ -172,7 +172,10 @@
 		mSliderH = LoadAttrIntScaleY(child, "sliderh", mSliderH);
 	}
 
-	mFontHeight = mFont->GetHeight();
+	if (mFont && mFont->GetResource())
+		mFontHeight = mFont->GetHeight();
+	else
+		mFontHeight = 0;
 
 	if (mShowCurr)
 	{