Remove ActionBar.LayoutParams MarginLayoutParams constructor

Adding this for L caused some fun issues with source compatibility.
Apps that previously passed another MarginLayoutParams subclass to
ActionBar.LayoutParams' constructor started statically linking to a
constructor overload that did not exist on older platform changes with
no other source changes. In the interests of avoiding these headaches
for developers, remove it.

Bug 15933193

Change-Id: I01cf8dfa2341b9d9629331639433b59352e7e15a

1 files changed, 9 insertions, 3 deletions

diff --git a/core/java/android/app/ActionBar.java b/core/java/android/app/ActionBar.java
index 628875f0218e..5c981802b0dc 100644
--- a/core/java/android/app/ActionBar.java
+++ b/core/java/android/app/ActionBar.java
@@ -1334,8 +1334,14 @@ public abstract class ActionBar {
             super(source);
         }
 
-        public LayoutParams(MarginLayoutParams source) {
-            super(source);
-        }
+        /*
+         * Note for framework developers:
+         *
+         * You might notice that ActionBar.LayoutParams is missing a constructor overload
+         * for MarginLayoutParams. While it may seem like a good idea to add one, at this
+         * point it's dangerous for source compatibility. Upon building against a new
+         * version of the SDK an app can end up statically linking to the new MarginLayoutParams
+         * overload, causing a crash when running on older platform versions with no other changes.
+         */
     }
 }