[WebLayer] Fix WebLayer module manifest getting stale

The WebLayer module's AndroidManifest.xml depends on the base module's
package name. The target that generates the manifest didn't realize the
generated manifest was stale when the base package name changed, which
caused build errors on the official bots.

Bug: 1129288
Change-Id: I488f484d3dd87fb5774cf669df96b6e3a2babd6e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2416892
Commit-Queue: Clark DuVall <cduvall@chromium.org>
Commit-Queue: Richard Coles <torne@chromium.org>
Auto-Submit: Clark DuVall <cduvall@chromium.org>
Reviewed-by: Richard Coles <torne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#807947}

android_webview/system_webview_bundle.gni

@@ -47,6 +47,9 @@ template("system_webview_bundle") {
                                "uncompress_shared_libraries",
                              ])
       android_manifest = "//weblayer/browser/java/AndroidManifest.xml"
+
+      # The manifest depends on the package name from the base build config.
+      android_manifest_dep = _base_module_build_config_target
       deps = [
         "//weblayer/browser/java",
         _base_module_build_config_target,