Adding margin to Drag layer instead of checking for right insets at every place

Bug: 25692432
Change-Id: I853f41a17c54b30b7772b9fd8556d9465de84752
diff --git a/src/com/android/launcher3/LauncherRootView.java b/src/com/android/launcher3/LauncherRootView.java
index 1c6ca87..71ccd85 100644
--- a/src/com/android/launcher3/LauncherRootView.java
+++ b/src/com/android/launcher3/LauncherRootView.java
@@ -1,17 +1,22 @@
 package com.android.launcher3;
 
+import android.annotation.TargetApi;
+import android.app.ActivityManager;
 import android.content.Context;
 import android.graphics.Canvas;
 import android.graphics.Color;
 import android.graphics.Paint;
 import android.graphics.Rect;
 import android.util.AttributeSet;
+import android.view.View;
 
 public class LauncherRootView extends InsettableFrameLayout {
 
     private final Paint mOpaquePaint;
     private boolean mDrawRightInsetBar;
 
+    private View mAlignedView;
+
     public LauncherRootView(Context context, AttributeSet attrs) {
         super(context, attrs);
 
@@ -21,10 +26,32 @@
     }
 
     @Override
+    protected void onFinishInflate() {
+        if (getChildCount() > 0) {
+            // LauncherRootView contains only one child, which should be aligned
+            // based on the horizontal insets.
+            mAlignedView = getChildAt(0);
+        }
+        super.onFinishInflate();
+    }
+
+    @TargetApi(23)
+    @Override
     protected boolean fitSystemWindows(Rect insets) {
-        setInsets(insets);
-        mDrawRightInsetBar = mInsets.right > 0 && LauncherAppState
-                .getInstance().getInvariantDeviceProfile().isRightInsetOpaque;
+        mDrawRightInsetBar = insets.right > 0 &&
+                (!Utilities.ATLEAST_MARSHMALLOW ||
+                getContext().getSystemService(ActivityManager.class).isLowRamDevice());
+        setInsets(mDrawRightInsetBar ? new Rect(0, insets.top, 0, insets.bottom) : insets);
+
+        if (mAlignedView != null) {
+            // Apply margins on aligned view to handle left/right insets.
+            MarginLayoutParams lp = (MarginLayoutParams) mAlignedView.getLayoutParams();
+            if (lp.leftMargin != insets.left || lp.rightMargin != insets.right) {
+                lp.leftMargin = insets.left;
+                lp.rightMargin = insets.right;
+                mAlignedView.setLayoutParams(lp);
+            }
+        }
 
         return true; // I'll take it from here
     }