Move session into //blimp/client/app and update GN files.

blimp/client/core/settings/BUILD.gn

Index: blimp/client/core/settings/BUILD.gn
diff --git a/blimp/client/core/settings/BUILD.gn b/blimp/client/core/settings/BUILD.gn
index 3f6cff6412ad24a6133148386b22ef085790aad6..39801cd928cc25ab55cc7761f9c14caa4912a12c 100644
--- a/blimp/client/core/settings/BUILD.gn
+++ b/blimp/client/core/settings/BUILD.gn
@@ -8,7 +8,10 @@ if (is_android) {
 }
 
 source_set("settings") {
-  visibility = [ "//blimp/client/*" ]
+  visibility = [
+    "//blimp/client/app:*",  # TODO(nyquist): Remove this. See crbug/651964.
+    "//blimp/client/core/*",
+  ]
 
   sources = [
     "blimp_settings_delegate.h",
@@ -42,7 +45,10 @@ source_set("settings") {
 
 if (is_android) {
   android_library("settings_java") {
-    visibility = [ "//blimp/client/*" ]
+    visibility = [
+      "//blimp/client/app:*",  # TODO(nyquist): Remove this. See crbug/651964.
+      "//blimp/client/core/*",
+    ]
 
     java_files = [
       "android/java/src/org/chromium/blimp/core/settings/AboutBlimpPreferences.java",
@@ -52,7 +58,7 @@ if (is_android) {
     # TODO(xingliu): Clean resources files in the future. http://crbug.com/630687.
     deps = [
       "//base:base_java",
-      "//blimp/client:blimp_java_resources",
+      "//blimp/client/app:blimp_java_resources",
       "//blimp/client/core/common:common_java",
       "//blimp/client/public:public_headers_java",
       "//components/signin/core/browser/android:java",