Show toolbar when DEG/RAD mode matters

Bug: 27926287
Bug: 28086262

Continue to show the toolbar when entering a formula containing trig
function calls.

This also changes the toolbar hiding logic a bit to make physical
keyboard input more like button presses.

No longer makes the tool bar visible on a long press, reserving
that for COPY or PASTE.

Change-Id: I30cb3d747e45b8fe24e35b20805a1d04bdf7b8c9
diff --git a/src/com/android/calculator2/CalculatorExpr.java b/src/com/android/calculator2/CalculatorExpr.java
index 2946b8b..764b054 100644
--- a/src/com/android/calculator2/CalculatorExpr.java
+++ b/src/com/android/calculator2/CalculatorExpr.java
@@ -979,6 +979,21 @@
     }
 
     /**
+     * Does the expression contain trig operations?
+     */
+    public boolean hasTrigFuncs() {
+        for (Token t: mExpr) {
+            if (t instanceof Operator) {
+                Operator o = (Operator)t;
+                if (KeyMaps.isTrigFunc(o.id)) {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+
+    /**
      * Evaluate the expression excluding trailing binary operators.
      * Errors result in exceptions, most of which are unchecked.  Should not be called
      * concurrently with modification of the expression.  May take a very long time; avoid calling