Move instant support to SearchTabHelper.

chrome/browser/ui/search/search_model.h

Index: chrome/browser/ui/search/search_model.h
diff --git a/chrome/browser/ui/search/search_model.h b/chrome/browser/ui/search/search_model.h
index 3f77b87c17383018f30bb64433abb9607f5d3ed1..07c26efe2ed6d549a9279675a3ba2012c5ecb261 100644
--- a/chrome/browser/ui/search/search_model.h
+++ b/chrome/browser/ui/search/search_model.h
@@ -11,25 +11,36 @@
 
 class SearchModelObserver;
 
+// Represents whether a page supports Instant.
+enum InstantSupportState {
+  INSTANT_SUPPORT_NO,
+  INSTANT_SUPPORT_YES,
+  INSTANT_SUPPORT_UNKNOWN,
+};
+
 // An observable model for UI components that care about search model state
 // changes.
 class SearchModel {
  public:
   struct State {
-    State() : top_bars_visible(true) {}
-    State(const SearchMode& mode, bool top_bars_visible)
-        : mode(mode),
-          top_bars_visible(top_bars_visible) {}
+    State();
+    State(const SearchMode& mode,
+          bool top_bars_visible,
+          InstantSupportState instant_support);
 
-    bool operator==(const State& rhs) const {
-      return mode == rhs.mode && top_bars_visible == rhs.top_bars_visible;
-    }
+    bool operator==(const State& rhs) const;
 
     // The display mode of UI elements such as the toolbar, the tab strip, etc.
     SearchMode mode;
 
     // The visibility of top bars such as bookmark and info bars.
     bool top_bars_visible;
+
+    // Does the current page support Instant?
+    //
+    // TODO(kmadhusu): Use bool instead of a tri-state variable. Refer to
+    // crbug.com/246323 for more details.
+    InstantSupportState instant_support;
   };
 
   SearchModel();
@@ -58,6 +69,15 @@ class SearchModel {
   // Get the visibility of top bars.
   bool top_bars_visible() const { return state_.top_bars_visible; }
 
+  // Set whether the page supports Instant. Change notifications are sent to
+  // observers.
+  void SetSupportsInstant(bool supports_instant);
+
+  // Get whether the page supports Instant.
+  InstantSupportState instant_support() const {
+    return state_.instant_support;
+  }
+
   // Add and remove observers.
   void AddObserver(SearchModelObserver* observer);
   void RemoveObserver(SearchModelObserver* observer);