Disable avatar and contextual cards on low ram devices.

Fixes: 124127763
Test: robotest & manually inspected hprof
Change-Id: I8d328b782a9b1871b76edf433d2378d06face14a

tests/robotests/src/com/android/settings/accounts/AvatarViewMixinTest.java

@@ -27,6 +27,7 @@ import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.verify;
 
 import android.accounts.Account;
+import android.app.ActivityManager;
 import android.content.ContentProvider;
 import android.content.ContentResolver;
 import android.content.Context;
@@ -55,6 +56,7 @@ import org.robolectric.annotation.Config;
 import org.robolectric.annotation.Implementation;
 import org.robolectric.annotation.Implements;
 import org.robolectric.shadow.api.Shadow;
+import org.robolectric.shadows.ShadowActivityManager;
 import org.robolectric.shadows.ShadowContentResolver;
 import org.robolectric.shadows.ShadowPackageManager;
 
@@ -100,6 +102,19 @@ public class AvatarViewMixinTest {
         verify(mixin, never()).hasAccount();
     }
 
+    @Test
+    public void onStart_lowRamDevice_doNothing() {
+        final AvatarViewMixin mixin = spy(new AvatarViewMixin(mActivity, mImageView));
+
+        final ShadowActivityManager activityManager =
+                Shadow.extract(mContext.getSystemService(ActivityManager.class));
+        activityManager.setIsLowRamDevice(true);
+
+        mixin.onStart();
+
+        verify(mixin, never()).hasAccount();
+    }
+
     @Test
     @Config(qualifiers = "mcc999",
             shadows = {