Clear contact info on low memory

app/src/main/java/eu/faircode/email/ApplicationEx.java

@@ -152,6 +152,9 @@ public class ApplicationEx extends Application {
         Map<String, String> crumb = new HashMap<>();
         crumb.put("free", Integer.toString(Log.getFreeMemMb()));
         Log.breadcrumb("low", crumb);
+
+        ContactInfo.clearCache(this, false);
+
         super.onLowMemory();
     }
 

app/src/main/java/eu/faircode/email/ContactInfo.java

@@ -138,12 +138,22 @@ public class ContactInfo {
     }
 
     static void clearCache(Context context) {
+        clearCache(context, true);
+    }
+
+    static void clearCache(Context context, boolean files) {
         synchronized (emailContactInfo) {
             emailContactInfo.clear();
         }
 
-        final File dir = new File(context.getCacheDir(), "favicons");
+        synchronized (emailGravatar) {
+            emailGravatar.clear();
+        }
+
+        if (!files)
+            return;
 
+        final File dir = new File(context.getCacheDir(), "favicons");
         executorFavicon.submit(new Runnable() {
             @Override
             public void run() {