weblayer: exposes NavigateParams#getResponse()

for testing. This was requested by Patricia.

BUG=none
TEST=none

Change-Id: I88c61ae43d02a611efbfc868861a10250144b838
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2640813Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Commit-Queue: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#845392}

weblayer/public/java/org/chromium/weblayer/NavigateParams.java

@@ -145,7 +145,7 @@ public class NavigateParams {
      *
      * @return WebResourceResponse of html to use.
      */
-    WebResourceResponse getResponse() {
+    public WebResourceResponse getResponse() {
         return mResponse;
     }
 }