Ensure that the front-most task never dims when scrolling the stack.

Change-Id: I370311b78203c079c4bbfa67753da13f91a15cbc
diff --git a/packages/SystemUI/src/com/android/systemui/recents/views/TaskStackLayoutAlgorithm.java b/packages/SystemUI/src/com/android/systemui/recents/views/TaskStackLayoutAlgorithm.java
index e908e53..1e3baa6 100644
--- a/packages/SystemUI/src/com/android/systemui/recents/views/TaskStackLayoutAlgorithm.java
+++ b/packages/SystemUI/src/com/android/systemui/recents/views/TaskStackLayoutAlgorithm.java
@@ -650,7 +650,11 @@
             y += (mStackRect.top - mTaskRect.top);
             z = Math.max(mMinTranslationZ, Math.min(mMaxTranslationZ,
                     mMinTranslationZ + (p * (mMaxTranslationZ - mMinTranslationZ))));
-            relP = unfocusedP;
+            if (mNumStackTasks == 1) {
+                relP = 1f;
+            } else {
+                relP = Math.min(mMaxScrollP, unfocusedP);
+            }
         }
 
         // Fill out the transform