Move instant support to SearchTabHelper.

chrome/browser/ui/search/search_model.cc

Index: chrome/browser/ui/search/search_model.cc
diff --git a/chrome/browser/ui/search/search_model.cc b/chrome/browser/ui/search/search_model.cc
index 53d0fcc9efd245bd685085d5c55051b98176cf6e..132b49a61b9e81eee33ea68dd8c15772a6390153 100644
--- a/chrome/browser/ui/search/search_model.cc
+++ b/chrome/browser/ui/search/search_model.cc
@@ -7,6 +7,24 @@
 #include "chrome/browser/search/search.h"
 #include "chrome/browser/ui/search/search_model_observer.h"
 
+SearchModel::State::State()
+    : top_bars_visible(true),
+      instant_support(INSTANT_SUPPORT_UNKNOWN) {
+}
+
+SearchModel::State::State(const SearchMode& mode,
+                          bool top_bars_visible,
+                          InstantSupportState instant_support)
+    : mode(mode),
+      top_bars_visible(top_bars_visible),
+      instant_support(instant_support) {
+}
+
+bool SearchModel::State::operator==(const State& rhs) const {
+  return mode == rhs.mode && top_bars_visible == rhs.top_bars_visible &&
+      instant_support == rhs.instant_support;
+}
+
 SearchModel::SearchModel() {
 }
 
@@ -77,6 +95,24 @@ void SearchModel::SetTopBarsVisible(bool visible) {
                     ModelChanged(old_state, state_));
 }
 
+void SearchModel::SetSupportsInstant(bool supports_instant) {

[samarth, 2013/05/10 01:32:38]

Can we follow Jered's lead in InstantPage and add some unit tests here as well? 
Some of the logic here is non trivial.

[kmadhusu, 2013/05/13 17:13:24]

Done.

+  DCHECK(chrome::IsInstantExtendedAPIEnabled())
+      << "Please do not try to set the SearchModel mode without first "
+      << "checking if Search is enabled.";
+
+  InstantSupportState new_instant_support = supports_instant ?
+      INSTANT_SUPPORT_YES : INSTANT_SUPPORT_NO;
+
+  if (state_.instant_support == new_instant_support)
+    return;
+
+  const State old_state = state_;
+  state_.instant_support = new_instant_support;
+
+  FOR_EACH_OBSERVER(SearchModelObserver, observers_,
+                    ModelChanged(old_state, state_));
+}
+
 void SearchModel::AddObserver(SearchModelObserver* observer) {
   observers_.AddObserver(observer);
 }