Add core plumbing for Instant Extended work

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
new file mode 100644
index 0000000000000000000000000000000000000000..8d98be1ab8bc6821efc7b89c97a10daa51774178
--- /dev/null
+++ b/chrome/browser/ui/search/search_model.cc
@@ -0,0 +1,56 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/ui/search/search_model.h"
+
+#include "chrome/browser/ui/search/search.h"
+#include "chrome/browser/ui/search/search_model_observer.h"
+#include "chrome/browser/ui/tab_contents/tab_contents.h"
+
+namespace chrome {
+namespace search {
+
+SearchModel::SearchModel(TabContents* contents)
+    : contents_(contents) {
+}
+
+SearchModel::~SearchModel() {
+}
+
+void SearchModel::SetMode(const Mode& mode) {
+  if (!contents_)
+    return;
+
+  DCHECK(IsInstantExtendedAPIEnabled(contents_->profile()))
+      << "Please do not try to set the SearchModel mode without first "
+      << "checking if Search is enabled.";
+
+  if (mode_ == mode)
+    return;
+
+  mode_ = mode;
+
+  FOR_EACH_OBSERVER(SearchModelObserver, observers_, ModeChanged(mode_));
+
+  // Animation is transient, it is cleared after observers are notified.
+  mode_.animate = false;
+}
+
+void SearchModel::MaybeChangeMode(Mode::Type from_mode, Mode::Type to_mode) {
+  if (mode_.mode == from_mode) {
+    Mode mode(to_mode, true);
+    SetMode(mode);
+  }
+}
+
+void SearchModel::AddObserver(SearchModelObserver* observer) {
+  observers_.AddObserver(observer);
+}
+
+void SearchModel::RemoveObserver(SearchModelObserver* observer) {
+  observers_.RemoveObserver(observer);
+}
+
+} //  namespace search
+} //  namespace chrome