weblayer: adds some more javadoc

BUG=none
TEST=none

Change-Id: I28be78610c709b4eebbb951afeee1dfbd3477c24
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1888786
Commit-Queue: Scott Violet <sky@chromium.org>
Reviewed-by: Darin Fisher <darin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#710820}

weblayer/public/java/org/chromium/weblayer/BrowserFragmentController.java

@@ -29,7 +29,11 @@ public final class BrowserFragmentController {
         mProfileManager = profileManager;
     }
 
-    // TODO(pshmakov): rename this to BrowserTabController.
+    /**
+     * Returns the BrowserController associated with this BrowserFragmentController.
+     *
+     * @return The BrowserController.
+     */
     @NonNull
     public BrowserController getBrowserController() {
         ThreadCheck.ensureOnUiThread();
@@ -43,6 +47,12 @@ public final class BrowserFragmentController {
         return mController;
     }
 
+    /**
+     * Sets the View shown at the top of the browser. A value of null removes the view. The
+     * top-view is typically used to show the uri. The top-view scrolls with the page.
+     *
+     * @param view The new top-view.
+     */
     public void setTopView(@Nullable View view) {
         ThreadCheck.ensureOnUiThread();
         try {