Split up ios/web:test_support.

ios/chrome/browser/metrics/BUILD.gn

Index: ios/chrome/browser/metrics/BUILD.gn
diff --git a/ios/chrome/browser/metrics/BUILD.gn b/ios/chrome/browser/metrics/BUILD.gn
index 91c6ea44aacf66bbdd3864582d1c5e92ebdeaec3..faa54a4ef9f5b14e31a2fbe3313f4020eaccee65 100644
--- a/ios/chrome/browser/metrics/BUILD.gn
+++ b/ios/chrome/browser/metrics/BUILD.gn
@@ -78,6 +78,7 @@ source_set("unit_tests") {
     "//components/prefs:test_support",
     "//components/version_info",
     "//ios/chrome/test:test_support",
+    "//ios/web/public/test:test_support",
     "//testing/gtest",
   ]
 }
@@ -144,7 +145,7 @@ source_set("unit_tests_internal") {
     "//ios/chrome/browser/ui",
     "//ios/testing:ocmock_support",
     "//ios/web",
-    "//ios/web:test_support",
+    "//ios/web/public/test:test_support",
     "//testing/gtest",
     "//third_party/ocmock",
   ]
@@ -170,7 +171,8 @@ source_set("eg_tests") {
     "//ios/chrome/test/earl_grey:test_support",
     "//ios/testing:ios_test_support",
     "//ios/web:earl_grey_test_support",
-    "//ios/web:test_support",
+    "//ios/web/public/test:test_support",
+    "//ios/web/public/test/response_providers:test_support",
     "//ui/base",
     "//url",
   ]
@@ -191,7 +193,7 @@ source_set("external_url_eg_tests") {
     ":test_support",
     "//ios/chrome/test/app:test_support",
     "//ios/chrome/test/earl_grey:test_support",
-    "//ios/web:test_support",
+    "//ios/web/public/test:test_support",
   ]
   libs = [ "XCTest.framework" ]
 }
@@ -210,6 +212,7 @@ source_set("test_support") {
     "//ios/chrome/test/app:test_support",
     "//ios/chrome/test/earl_grey:test_support",
     "//ios/testing:ios_test_support",
+    "//ios/web/public/test:test_support",
     "//ui/base",
   ]
   configs += [ "//build/config/compiler:enable_arc" ]