Move manifest_url_handler to //extensions

This moves extensions manifest URL handlers into //extensions
and renames the source files more appropriately to
"manifest_url_handlers"

Mechanical change, so all this noise is only header updates.

TBRs are for header changes only.

BUG=398671
[email protected] for app_mode change
[email protected] for themes change
[email protected] for ui changes

Review URL: https://codereview.chromium.org/651353002

Cr-Commit-Position: refs/heads/master@{#299598}
diff --git a/chrome/browser/extensions/extension_service.cc b/chrome/browser/extensions/extension_service.cc
index 629e04e..56838a7 100644
--- a/chrome/browser/extensions/extension_service.cc
+++ b/chrome/browser/extensions/extension_service.cc
@@ -54,7 +54,6 @@
 #include "chrome/common/crash_keys.h"
 #include "chrome/common/extensions/extension_constants.h"
 #include "chrome/common/extensions/features/feature_channel.h"
-#include "chrome/common/extensions/manifest_url_handler.h"
 #include "chrome/common/url_constants.h"
 #include "components/crx_file/id_util.h"
 #include "components/startup_metric_utils/startup_metric_utils.h"
@@ -79,6 +78,7 @@
 #include "extensions/common/file_util.h"
 #include "extensions/common/manifest_constants.h"
 #include "extensions/common/manifest_handlers/background_info.h"
+#include "extensions/common/manifest_url_handlers.h"
 #include "extensions/common/one_shot_event.h"
 #include "extensions/common/permissions/permission_message_provider.h"
 #include "extensions/common/permissions/permissions_data.h"