Add core plumbing for Instant Extended work

chrome/browser/ui/search/search_types.h

Index: chrome/browser/ui/search/search_types.h
diff --git a/chrome/browser/ui/search/search_types.h b/chrome/browser/ui/search/search_types.h
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+++ b/chrome/browser/ui/search/search_types.h
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+// 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.
+
+#ifndef CHROME_BROWSER_UI_SEARCH_SEARCH_TYPES_H_
+#define CHROME_BROWSER_UI_SEARCH_SEARCH_TYPES_H_
+#pragma once
+
+namespace chrome {
+namespace search {
+
+// The Mode structure encodes the visual states encountered when interacting
+// with the NTP and the Omnibox.  State changes can be animated depending on the
+// context.
+struct Mode {
+  enum Type {
+    // The default state means anything but the following states.
+    MODE_DEFAULT,
+
+    // On the NTP page but the NTP isn't in a state that we should show it.
+    MODE_NTP_LOADING,
+
+    // On the NTP page and the NTP is ready to be displayed.
+    MODE_NTP,
+
+    // Any of the following:
+    // . on the NTP page and the Omnibox is modified in some way.
+    // . on a search results page.
+    // . the Omnibox has focus.
+    MODE_SEARCH,
+  };
+
+  Mode() : mode(MODE_DEFAULT), animate(false) {
+  }
+
+  Mode(Type in_mode, bool in_animate) : mode(in_mode), animate(in_animate) {
+  }
+
+  bool operator==(const Mode& rhs) const {
+    return mode == rhs.mode;
+    // |animate| is transient.  It doesn't count.
+  }
+
+  bool is_default() const {
+    return mode == MODE_DEFAULT;
+  }
+
+  bool is_ntp() const {
+    return mode == MODE_NTP || mode == MODE_NTP_LOADING;
+  }
+
+  bool is_search() const {
+    return mode == MODE_SEARCH;
+  }
+
+  Type mode;
+
+  // Mode changes can be animated.  This is transient state, once a call to
+  // |SearchModel::SetMode| has completed and its observers notified |animate|
+  // is set to |false|.
+  bool animate;
+};
+
+}  // namespace search
+}  // namespace chrome
+
+#endif  // CHROME_BROWSER_UI_SEARCH_SEARCH_TYPES_H_