html_viewer: Move webcrypto to a place where html_viewer can use it.

content/child/BUILD.gn

Index: content/child/BUILD.gn
diff --git a/content/child/BUILD.gn b/content/child/BUILD.gn
index c567f4eb8f5de50e014f3a283228f6f572ebf481..fe296dd32b1528a5fb7fd32e4f394558621257ec 100644
--- a/content/child/BUILD.gn
+++ b/content/child/BUILD.gn
@@ -23,6 +23,7 @@ source_set("child") {
   deps = [
     "//base",
     "//components/tracing",
+    "//components/webcrypto",
     "//content/common:mojo_bindings",
     "//mojo/common",
     "//mojo/environment:chromium",
@@ -128,14 +129,4 @@ source_set("child") {
   if (is_win || !use_aura) {
     sources -= [ "npapi/webplugin_delegate_impl_aura.cc" ]
   }
-
-  if (!use_openssl) {
-    sources += rebase_path(content_child_gypi_values.webcrypto_nss_sources,
-                           ".",
-                           "//content")
-  } else {
-    sources += rebase_path(content_child_gypi_values.webcrypto_openssl_sources,
-                           ".",
-                           "//content")
-  }
 }