Remaining changes to build all code in src.git with -Wimplicit-fallthrough.

This CL was uploaded by git cl split.

R=tbarzic@chromium.org

Bug: 177475
Change-Id: Ie043227144ac242f6c4939f54e59370e1c65743e
Reviewed-on: https://chromium-review.googlesource.com/891780Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#533021}

extensions/browser/api/management/management_api.cc

@@ -214,6 +214,7 @@ management::ExtensionInfo CreateExtensionInfo(
       break;
     case Manifest::NUM_LOCATIONS:
       NOTREACHED();
+      FALLTHROUGH;
     case Manifest::INVALID_LOCATION:
     case Manifest::COMPONENT:
     case Manifest::EXTERNAL_COMPONENT: