Removed keeps for unused member variables.

chrome/android/java/proguard.flags

Index: chrome/android/java/proguard.flags
diff --git a/chrome/android/java/proguard.flags b/chrome/android/java/proguard.flags
index d0f19e3e4293f77be6fc3cb6340668a511961e39..627ae0d1674e93830d93ece6921628613fedac48 100644
--- a/chrome/android/java/proguard.flags
+++ b/chrome/android/java/proguard.flags
@@ -223,3 +223,10 @@
 # Needed for chrome_sync_shell_test_apk. Note - these do no affect chrome_apk's
 # size.
 -keep class org.chromium.sync.protocol.* { *; }
+
+# These resources are referenced in tests, but not in the real application.
+-keepclassmembers class org.chromium.chrome.R$id {
+  int webapp_splash_space;
+  int mr_chooser_list;
+  int find_toolbar;
+}