Upstream Chrome on iOS source code [10/11].

ios/chrome/browser/ui/util/snapshot_util.mm

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#import "ios/chrome/browser/ui/util/snapshot_util.h"
+
+namespace snapshot_util {
+
+UIView* GenerateSnapshot(UIView* view) {
+  UIView* snapshot;
+  if (view.window) {
+    // |view| is in a view hierarchy.
+    snapshot = [view snapshotViewAfterScreenUpdates:NO];
+  } else {
+    UIGraphicsBeginImageContextWithOptions(view.bounds.size, NO, 0);
+    [view.layer renderInContext:UIGraphicsGetCurrentContext()];
+    UIImage* screenshot = UIGraphicsGetImageFromCurrentImageContext();
+    UIGraphicsEndImageContext();
+    snapshot = [[[UIView alloc] initWithFrame:CGRectZero] autorelease];
+    snapshot.layer.contents = static_cast<id>(screenshot.CGImage);
+  }
+  return snapshot;
+}
+
+}  // namespace snapshot_util