move scroll_overlay to sub-directory and add licenses, authors

Author: xster

AUTHORS

@@ -0,0 +1,6 @@
+# Below is a list of people and organizations that have contributed
+# to the Flutter project. Names should be added to the list like so:
+#
+#   Name/Organization <email address>
+
+Google Inc.

LICENSE

@@ -0,0 +1,25 @@
+Copyright 2019 The Chromium Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without modification,
+are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+    * Neither the name of Google Inc. nor the names of its
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

PATENTS

@@ -0,0 +1,17 @@
+Google hereby grants to you a perpetual, worldwide, non-exclusive,
+no-charge, royalty-free, irrevocable (except as stated in this
+section) patent license to make, have made, use, offer to sell, sell,
+import, transfer, and otherwise run, modify and propagate the contents
+of this implementation, where such license applies only to those
+patent claims, both currently owned by Google and acquired in the
+future, licensable by Google that are necessarily infringed by this
+implementation. This grant does not include claims that would be
+infringed only as a consequence of further modification of this
+implementation. If you or your agent or exclusive licensee institute
+or order or agree to the institution of patent litigation or any other
+patent enforcement activity against any entity (including a
+cross-claim or counterclaim in a lawsuit) alleging that this
+implementation constitutes direct or contributory patent infringement,
+or inducement of patent infringement, then any patent rights granted
+to you under this License for this implementation shall terminate as
+of the date such litigation is filed.