Allow LauncherOverlay to access and manage insets

Change-Id: Ib9faf37eb22ad2a0b18c076978ec9f2fd8864c0c

src/com/android/launcher3/InsettableFrameLayout.java

@@ -0,0 +1,52 @@
+package com.android.launcher3;
+
+import android.content.Context;
+import android.graphics.Rect;
+import android.util.AttributeSet;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.FrameLayout;
+
+public class InsettableFrameLayout extends FrameLayout implements
+    ViewGroup.OnHierarchyChangeListener, Insettable {
+
+    protected Rect mInsets = new Rect();
+
+    public InsettableFrameLayout(Context context, AttributeSet attrs) {
+        super(context, attrs);
+        setOnHierarchyChangeListener(this);
+    }
+
+    public void setFrameLayoutChildInsets(View child, Rect newInsets, Rect oldInsets) {
+        final FrameLayout.LayoutParams flp = (FrameLayout.LayoutParams) child.getLayoutParams();
+        if (child instanceof Insettable) {
+            ((Insettable) child).setInsets(newInsets);
+        } else {
+            flp.topMargin += (newInsets.top - oldInsets.top);
+            flp.leftMargin += (newInsets.left - oldInsets.left);
+            flp.rightMargin += (newInsets.right - oldInsets.right);
+            flp.bottomMargin += (newInsets.bottom - oldInsets.bottom);
+        }
+        child.setLayoutParams(flp);
+    }
+
+    @Override
+    public void setInsets(Rect insets) {
+        final int n = getChildCount();
+        for (int i = 0; i < n; i++) {
+            final View child = getChildAt(i);
+            setFrameLayoutChildInsets(child, insets, mInsets);
+        }
+        mInsets.set(insets);
+    }
+
+    @Override
+    public void onChildViewAdded(View parent, View child) {
+        setFrameLayoutChildInsets(child, mInsets, new Rect());
+    }
+
+    @Override
+    public void onChildViewRemoved(View parent, View child) {
+    }
+
+}