[base] Apply BindOnceRewriter in //android_webview

This change applies the BindOnceRewriter in //android_webview.
This rewriter replaces calls to base::Bind and base::BindRepeating with
calls to base::BindOnce, in case the result is immediately assigned to a
base::OnceCallback. Given that base::RepeatingCallback is implicitly
convertible to base::OnceCallback, there is no change in functionality.

Steps:
  1. run_tool.py --tool base_bind_rewriters \
                 --tool-arg='--rewriter=bind_to_bind_once'
  2. git cl format

This CL was uploaded by git cl split.

R=changwan@chromium.org

Bug: 714018
Change-Id: Idb3efb3cb232b948d227c4bd238327e3556afae7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2132148
Auto-Submit: Jan Wilken Dörrie <jdoerrie@chromium.org>
Reviewed-by: Changwan Ryu <changwan@chromium.org>
Commit-Queue: Changwan Ryu <changwan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#755424}

android_webview/browser/permission/media_access_permission_request_unittest.cc

@@ -60,8 +60,8 @@ class MediaAccessPermissionRequestTest : public testing::Test {
     std::unique_ptr<TestMediaAccessPermissionRequest> permission_request;
     permission_request.reset(new TestMediaAccessPermissionRequest(
         request,
-        base::BindRepeating(&MediaAccessPermissionRequestTest::Callback,
-                            base::Unretained(this)),
+        base::BindOnce(&MediaAccessPermissionRequestTest::Callback,
+                       base::Unretained(this)),
         audio_devices, video_devices));
     return permission_request;
   }