Enabling metalava by default

Enabled metalava in buildSrc/**/SupportLibraryExtension.kt
Copied all api files from commit d06ee86f3d93a6a5376b0ec39f4c8acb93f77455 (the previous time we tried switching from Doclava to Metalava).
Reran `./gradlew updateApi` to regenerate any current api txt files

Bug: 72330103

Change-Id: I9aab950311f8fc68cc5629bd578bc938329ee375
diff --git a/customview/api/current.txt b/customview/api/current.txt
index a07bfc14..03155c6 100644
--- a/customview/api/current.txt
+++ b/customview/api/current.txt
@@ -1,14 +1,15 @@
+// Signature format: 2.0
 package androidx.customview.view {
 
   public abstract class AbsSavedState implements android.os.Parcelable {
     ctor protected AbsSavedState(android.os.Parcelable);
     ctor protected AbsSavedState(android.os.Parcel);
-    ctor protected AbsSavedState(android.os.Parcel, java.lang.ClassLoader);
+    ctor protected AbsSavedState(android.os.Parcel, ClassLoader?);
     method public int describeContents();
-    method public final android.os.Parcelable getSuperState();
-    method public void writeToParcel(android.os.Parcel, int);
-    field public static final android.os.Parcelable.Creator<androidx.customview.view.AbsSavedState> CREATOR;
-    field public static final androidx.customview.view.AbsSavedState EMPTY_STATE;
+    method public final android.os.Parcelable? getSuperState();
+    method public void writeToParcel(android.os.Parcel!, int);
+    field public static final android.os.Parcelable.Creator<androidx.customview.view.AbsSavedState>! CREATOR;
+    field public static final androidx.customview.view.AbsSavedState! EMPTY_STATE;
   }
 
 }
@@ -21,15 +22,15 @@
     method public final boolean dispatchHoverEvent(android.view.MotionEvent);
     method public final boolean dispatchKeyEvent(android.view.KeyEvent);
     method public final int getAccessibilityFocusedVirtualViewId();
-    method public deprecated int getFocusedVirtualView();
+    method @Deprecated public int getFocusedVirtualView();
     method public final int getKeyboardFocusedVirtualViewId();
     method protected abstract int getVirtualViewAt(float, float);
-    method protected abstract void getVisibleVirtualViews(java.util.List<java.lang.Integer>);
+    method protected abstract void getVisibleVirtualViews(java.util.List<java.lang.Integer>!);
     method public final void invalidateRoot();
     method public final void invalidateVirtualView(int);
     method public final void invalidateVirtualView(int, int);
-    method public final void onFocusChanged(boolean, int, android.graphics.Rect);
-    method protected abstract boolean onPerformActionForVirtualView(int, int, android.os.Bundle);
+    method public final void onFocusChanged(boolean, int, android.graphics.Rect?);
+    method protected abstract boolean onPerformActionForVirtualView(int, int, android.os.Bundle?);
     method protected void onPopulateEventForHost(android.view.accessibility.AccessibilityEvent);
     method protected void onPopulateEventForVirtualView(int, android.view.accessibility.AccessibilityEvent);
     method protected void onPopulateNodeForHost(androidx.core.view.accessibility.AccessibilityNodeInfoCompat);
@@ -49,21 +50,21 @@
     method public boolean checkTouchSlop(int);
     method public boolean checkTouchSlop(int, int);
     method public boolean continueSettling(boolean);
-    method public static androidx.customview.widget.ViewDragHelper create(android.view.ViewGroup, androidx.customview.widget.ViewDragHelper.Callback);
-    method public static androidx.customview.widget.ViewDragHelper create(android.view.ViewGroup, float, androidx.customview.widget.ViewDragHelper.Callback);
-    method public android.view.View findTopChildUnder(int, int);
+    method public static androidx.customview.widget.ViewDragHelper! create(android.view.ViewGroup, androidx.customview.widget.ViewDragHelper.Callback);
+    method public static androidx.customview.widget.ViewDragHelper! create(android.view.ViewGroup, float, androidx.customview.widget.ViewDragHelper.Callback);
+    method public android.view.View? findTopChildUnder(int, int);
     method public void flingCapturedView(int, int, int, int);
     method public int getActivePointerId();
-    method public android.view.View getCapturedView();
-    method public int getEdgeSize();
+    method public android.view.View? getCapturedView();
+    method @Px public int getEdgeSize();
     method public float getMinVelocity();
-    method public int getTouchSlop();
+    method @Px public int getTouchSlop();
     method public int getViewDragState();
     method public boolean isCapturedViewUnder(int, int);
     method public boolean isEdgeTouched(int);
     method public boolean isEdgeTouched(int, int);
     method public boolean isPointerDown(int);
-    method public boolean isViewUnder(android.view.View, int, int);
+    method public boolean isViewUnder(android.view.View?, int, int);
     method public void processTouchEvent(android.view.MotionEvent);
     method public void setEdgeTrackingEnabled(int);
     method public void setMinVelocity(float);
@@ -84,7 +85,7 @@
     field public static final int STATE_SETTLING = 2; // 0x2
   }
 
-  public static abstract class ViewDragHelper.Callback {
+  public abstract static class ViewDragHelper.Callback {
     ctor public ViewDragHelper.Callback();
     method public int clampViewPositionHorizontal(android.view.View, int, int);
     method public int clampViewPositionVertical(android.view.View, int, int);
@@ -96,7 +97,7 @@
     method public void onEdgeTouched(int, int);
     method public void onViewCaptured(android.view.View, int);
     method public void onViewDragStateChanged(int);
-    method public void onViewPositionChanged(android.view.View, int, int, int, int);
+    method public void onViewPositionChanged(android.view.View, int, int, @Px int, @Px int);
     method public void onViewReleased(android.view.View, float, float);
     method public abstract boolean tryCaptureView(android.view.View, int);
   }