Add a chrome://webapks page.

Adds an about:webapks page with information about all installed Web APKs
on the device

Design doc: go/about-webapks

BUG=624111
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2629573004
Cr-Commit-Position: refs/heads/master@{#448747}
diff --git a/chrome/browser/BUILD.gn b/chrome/browser/BUILD.gn
index d9dc545..9b896b7 100644
--- a/chrome/browser/BUILD.gn
+++ b/chrome/browser/BUILD.gn
@@ -2870,6 +2870,8 @@
       "android/webapk/chrome_webapk_host.h",
       "android/webapk/webapk_icon_hasher.cc",
       "android/webapk/webapk_icon_hasher.h",
+      "android/webapk/webapk_info.cc",
+      "android/webapk/webapk_info.h",
       "android/webapk/webapk_install_service.cc",
       "android/webapk/webapk_install_service.h",
       "android/webapk/webapk_install_service_factory.cc",