Revert of [Contextual Search] Remove opt-in code.

chrome/android/java/src/org/chromium/chrome/browser/compositor/bottombar/contextualsearch/ContextualSearchPanelStateHandler.java

Index: chrome/android/java/src/org/chromium/chrome/browser/compositor/bottombar/contextualsearch/ContextualSearchPanelStateHandler.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/compositor/bottombar/contextualsearch/ContextualSearchPanelStateHandler.java b/chrome/android/java/src/org/chromium/chrome/browser/compositor/bottombar/contextualsearch/ContextualSearchPanelStateHandler.java
index 6a8815b81a05606d103ff15001be9fd355db5c91..55d10ee4e2c3792ca74142eed01d69bf3bfcdece 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/compositor/bottombar/contextualsearch/ContextualSearchPanelStateHandler.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/compositor/bottombar/contextualsearch/ContextualSearchPanelStateHandler.java
@@ -18,7 +18,18 @@
  */
 abstract class ContextualSearchPanelStateHandler {
 
-    // Valid previous states for the Panel.
+    // Valid previous states for when the promo is active.
+    private static final Map<PanelState, PanelState> PREVIOUS_STATES_PROMO;
+    static {
+        Map<PanelState, PanelState> states = new HashMap<PanelState, PanelState>();
+        // Pairs are of the form <Current, Previous>.
+        states.put(PanelState.PEEKED, PanelState.CLOSED);
+        states.put(PanelState.PROMO, PanelState.PEEKED);
+        states.put(PanelState.EXPANDED, PanelState.PROMO);
+        PREVIOUS_STATES_PROMO = Collections.unmodifiableMap(states);
+    }
+
+    // Valid previous states for when the promo is not active (normal flow).
     private static final Map<PanelState, PanelState> PREVIOUS_STATES_NORMAL;
     static {
         Map<PanelState, PanelState> states = new HashMap<PanelState, PanelState>();
@@ -60,8 +71,26 @@
      * @return The {@code PanelState} that is before the |state| in the order of states.
      */
     PanelState getPreviousPanelState(PanelState state) {
-        PanelState prevState = PREVIOUS_STATES_NORMAL.get(state);
+        PanelState prevState = mIsPromoActive
+                ? PREVIOUS_STATES_PROMO.get(state)
+                : PREVIOUS_STATES_NORMAL.get(state);
         return prevState != null ? prevState : PanelState.UNDEFINED;
+    }
+
+    /**
+     * Return the maximum state that the panel can be in, depending on whether the promo is
+     * active.
+     */
+    PanelState getMaximumState() {
+        return mIsPromoActive ? PanelState.PROMO : PanelState.MAXIMIZED;
+    }
+
+    /**
+     * Return the intermediary state that the panel can be in, depending on whether the promo is
+     * active.
+     */
+    PanelState getIntermediaryState() {
+        return mIsPromoActive ? PanelState.PROMO : PanelState.EXPANDED;
     }
 
     /**
@@ -169,10 +198,14 @@
      * @return whether the state is valid.
      */
     boolean isValidState(PanelState state) {
-        ArrayList<PanelState> validStates =
-                new ArrayList<PanelState>(PREVIOUS_STATES_NORMAL.values());
-        // MAXIMIZED is not the previous state of anything, but it's a valid state.
-        validStates.add(PanelState.MAXIMIZED);
+        ArrayList<PanelState> validStates;
+        if (mIsPromoActive) {
+            validStates = new ArrayList<PanelState>(PREVIOUS_STATES_PROMO.values());
+        } else {
+            validStates = new ArrayList<PanelState>(PREVIOUS_STATES_NORMAL.values());
+            // MAXIMIZED is not the previous state of anything, but it's a valid state.
+            validStates.add(PanelState.MAXIMIZED);
+        }
 
         return validStates.contains(state);
     }