Add Settings[, Oberser] java code and JNI bridge.

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 ad1e6f239166214e8f201b110743aa51af4d48b7..d5bb906139658e8b79ee7c9270e2df0031cea7e9 100644
--- a/blimp/client/core/settings/BUILD.gn
+++ b/blimp/client/core/settings/BUILD.gn
@@ -40,6 +40,10 @@ source_set("settings") {
     sources += [
       "android/blimp_settings_android.cc",
       "android/blimp_settings_android.h",
+      "android/settings_android.cc",
+      "android/settings_android.h",
+      "android/settings_observer_proxy.cc",
+      "android/settings_observer_proxy.h",
     ]
 
     deps += [
@@ -79,6 +83,10 @@ if (is_android) {
     java_files = [
       "android/java/src/org/chromium/blimp/core/settings/AboutBlimpPreferences.java",
       "android/java/src/org/chromium/blimp/core/settings/BlimpPreferencesDelegate.java",
+      "android/java/src/org/chromium/blimp/core/settings/EmptySettingsObserver.java",
+      "android/java/src/org/chromium/blimp/core/settings/Settings.java",
+      "android/java/src/org/chromium/blimp/core/settings/SettingsObserver.java",
+      "android/java/src/org/chromium/blimp/core/settings/SettingsObserverProxy.java",
     ]
 
     # TODO(xingliu): Clean resources files in the future. http://crbug.com/630687.
@@ -98,6 +106,8 @@ if (is_android) {
 
     sources = [
       "android/java/src/org/chromium/blimp/core/settings/AboutBlimpPreferences.java",
+      "android/java/src/org/chromium/blimp/core/settings/Settings.java",
+      "android/java/src/org/chromium/blimp/core/settings/SettingsObserverProxy.java",
     ]
 
     jni_package = "blimp/client/core/settings"