Start of UI provider

This is the start of the contract for a UI provider, and also includes a
mock content provider implementing it.

Included is a unit test that just traverses the content provider

Change-Id: I4424e140830244f02eac204d71152dfc196c9741
diff --git a/proguard.flags b/proguard.flags
new file mode 100644
index 0000000..8a87290
--- /dev/null
+++ b/proguard.flags
@@ -0,0 +1,25 @@
+# The support library contains references to newer platform versions.
+# Don't warn about those in case this app is linking against an older
+# platform version.  We know about them, and they are safe.
+
+-dontwarn android.support.v4.**
+-dontwarn android.support.v13.**
+
+# keep names that are used by reflection, from javascript or from unit tests
+
+-keepclasseswithmembers class com.android.email.providers.MockUiProvider {
+  *** getAccountsUri(...);
+}
+
+-keepclasseswithmembers class com.android.email.providers.UIProvider {
+  *** getAccountsUri(...);
+}
+
+-keepclasseswithmembers class com.android.email.utils.LogUtils {
+  public <methods>;
+}
+
+
+-keepclasseswithmembers class com.google.common.collect.Sets {
+  *** of(...);
+}