Componentize conversion of content::FaviconURL to favicon::FaviconURL

In preparation of componentization of FaviconTabHelper, introduce a
new target //components/favicon/content (as favicon is a layered
component) and move the function to convert from content::FaviconURL
to favicon::FaviconURL there.

BUG=374281

Review URL: https://codereview.chromium.org/1020213002

Cr-Commit-Position: refs/heads/master@{#321606}
diff --git a/chrome/browser/BUILD.gn b/chrome/browser/BUILD.gn
index 3a0ed2e..b5af194 100644
--- a/chrome/browser/BUILD.gn
+++ b/chrome/browser/BUILD.gn
@@ -93,8 +93,8 @@
     "//components/device_event_log",
     "//components/domain_reliability",
     "//components/enhanced_bookmarks",
-    "//components/favicon_base",
     "//components/favicon/core",
+    "//components/favicon_base",
     "//components/gcm_driver",
     "//components/google/core/browser",
     "//components/handoff",
@@ -234,6 +234,7 @@
       "//components/autofill/content/browser",
       "//components/data_reduction_proxy/content/browser",
       "//components/dom_distiller/content",
+      "//components/favicon/content",
       "//components/history/content/browser",
       "//components/keyed_service/content",
       "//components/navigation_interception",