Update GN build files for new prefs location.

components/data_reduction_proxy/core/browser/BUILD.gn

Index: components/data_reduction_proxy/core/browser/BUILD.gn
diff --git a/components/data_reduction_proxy/core/browser/BUILD.gn b/components/data_reduction_proxy/core/browser/BUILD.gn
index 69f3344e959196a1614a3077a4d234292eb0980d..77ef2a4027990f8852f74eb55f593821b2462f6c 100644
--- a/components/data_reduction_proxy/core/browser/BUILD.gn
+++ b/components/data_reduction_proxy/core/browser/BUILD.gn
@@ -57,10 +57,10 @@ if (is_android) {
 
     deps = [
       "//base",
-      "//base:prefs",
       "//components/data_reduction_proxy/core/common:common_small",
       "//components/data_reduction_proxy/proto:data_reduction_proxy_proto",
       "//components/pref_registry",
+      "//components/prefs",
       "//components/variations",
       "//crypto",
       "//google_apis:google_apis_small",
@@ -79,10 +79,10 @@ source_set("browser") {
 
   deps = [
     "//base",
-    "//base:prefs",
     "//components/data_reduction_proxy/core/common",
     "//components/data_reduction_proxy/proto:data_reduction_proxy_proto",
     "//components/pref_registry",
+    "//components/prefs",
     "//components/variations",
     "//crypto",
     "//google_apis",
@@ -117,9 +117,9 @@ source_set("test_support") {
   ]
   deps = [
     "//base",
-    "//base:prefs_test_support",
     "//components/data_reduction_proxy/core/common",
     "//components/data_reduction_proxy/core/common:test_support",
+    "//components/prefs:test_support",
     "//net",
     "//net:test_support",
     "//testing/gmock",
@@ -156,10 +156,10 @@ source_set("unit_tests") {
     ":browser",
     ":test_support",
     "//base",
-    "//base:prefs_test_support",
     "//base/test:test_support",
     "//components/data_reduction_proxy/core/common:test_support",
     "//components/data_reduction_proxy/proto:data_reduction_proxy_proto",
+    "//components/prefs:test_support",
     "//components/variations",
     "//net:test_support",
     "//testing/gmock",