Componentize devtools_http_handler.

This moves DevToolsHttpHandler into it's own component.
It still depends on content::DevToolsTarget, which will be moved to
devtools_discovery component next.

BUG=476496

Review URL: https://codereview.chromium.org/1089413002

Cr-Commit-Position: refs/heads/master@{#325849}
diff --git a/chrome/browser/BUILD.gn b/chrome/browser/BUILD.gn
index 80b2f9b..adb4c14 100644
--- a/chrome/browser/BUILD.gn
+++ b/chrome/browser/BUILD.gn
@@ -239,6 +239,7 @@
       "//components/autofill/content/browser",
       "//components/browsing_data",
       "//components/data_reduction_proxy/content/browser",
+      "//components/devtools_http_handler",
       "//components/dom_distiller/content",
       "//components/favicon/content",
       "//components/history/content/browser",