Split //ios/chrome/browser in multiple targets.

ios/chrome/browser/signin/BUILD.gn

Index: ios/chrome/browser/signin/BUILD.gn
diff --git a/ios/chrome/browser/signin/BUILD.gn b/ios/chrome/browser/signin/BUILD.gn
index 744ee3e29cf9aa32cd20b808bbac3169e4feb850..58cd547edaac2f7a84a170194a32277b3de25e26 100644
--- a/ios/chrome/browser/signin/BUILD.gn
+++ b/ios/chrome/browser/signin/BUILD.gn
@@ -50,6 +50,12 @@ source_set("signin") {
   deps = [
     "//components/browser_sync",
     "//components/sync",
+    "//ios/chrome/browser:browser_no_public_deps",

[rohitrao (ping after 24h), 2016/10/25 19:48:53]

Why didn't we need any of these deps before?  Were we getting them transitively?
 How?

[sdefresne, 2016/10/25 21:10:23]

Yes, they were part of //ios/chrome/browser and //ios/chrome/browser/signin was
in its allow_circular_includes_from list.

+    "//ios/chrome/browser/bookmarks:bookmarks_utils",
+    "//ios/chrome/browser/browser_state",
+    "//ios/chrome/browser/content_settings",
+    "//ios/chrome/browser/crash_report",
+    "//ios/chrome/browser/ui/commands",
     "//ios/web",
     "//url",
   ]
@@ -115,7 +121,7 @@ source_set("unit_tests") {
     "//google_apis",
     "//ios/chrome/browser",
     "//ios/chrome/browser:test_support",
-    "//ios/chrome/test",
+    "//ios/chrome/test:test_support",
     "//ios/public/provider/chrome/browser",
     "//ios/public/provider/chrome/browser:test_support",
     "//ios/web:test_support",