[WebLayer] Add missing initialization bits for safebrowsing.

In this patch:
- Add safebrowsing threat types to watch (currently malware,
  phishing, unwanted and billing). This is needed by the
  RemoteSafeBrowsingDatabaseManager.
- Create and set native SafeBrowsingApiHandlerBridge during
  initialization. This is needed for native <-> java
  interactions.

BUG=1015418

Change-Id: I2ea97435a6e3885382ca6cad163337acd17dafa4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1901045
Reviewed-by: Richard Coles <[email protected]>
Commit-Queue: Tim Volodine <[email protected]>
Cr-Commit-Position: refs/heads/master@{#713419}
diff --git a/weblayer/BUILD.gn b/weblayer/BUILD.gn
index d6d637a..f41abce 100644
--- a/weblayer/BUILD.gn
+++ b/weblayer/BUILD.gn
@@ -169,6 +169,7 @@
       "//components/crash/android:crashpad_main",
       "//components/safe_browsing",
       "//components/safe_browsing/android:remote_database_manager",
+      "//components/safe_browsing/android:safe_browsing_api_handler",
       "//components/safe_browsing/browser",
       "//components/safe_browsing/browser:network_context",
       "//components/safe_browsing/db:database_manager",