Move instant support to SearchTabHelper. Fix InstantTab reset.

chrome/browser/ui/search/instant_page.cc

Index: chrome/browser/ui/search/instant_page.cc
diff --git a/chrome/browser/ui/search/instant_page.cc b/chrome/browser/ui/search/instant_page.cc
index f1ae57f07de3e3e52d1f5be1f082167c0b2ae647..de881d953c13ac5f87d248bd503596bc80aec58f 100644
--- a/chrome/browser/ui/search/instant_page.cc
+++ b/chrome/browser/ui/search/instant_page.cc
@@ -5,6 +5,9 @@
 #include "chrome/browser/ui/search/instant_page.h"
 
 #include "base/utf_string_conversions.h"
+#include "chrome/browser/search/search.h"
+#include "chrome/browser/ui/search/search_model.h"
+#include "chrome/browser/ui/search/search_tab_helper.h"
 #include "chrome/common/render_messages.h"
 #include "chrome/common/url_constants.h"
 #include "content/public/browser/web_contents.h"
@@ -15,6 +18,8 @@ InstantPage::Delegate::~Delegate() {
 }
 
 InstantPage::~InstantPage() {
+  if (extended_enabled_ && contents())
+    GetSearchModel()->RemoveObserver(this);
 }
 
 bool InstantPage::IsLocal() const {
@@ -107,11 +112,24 @@ void InstantPage::SendMostVisitedItems(
 InstantPage::InstantPage(Delegate* delegate, const std::string& instant_url)
     : delegate_(delegate),
       instant_url_(instant_url),
+      extended_enabled_(chrome::IsInstantExtendedAPIEnabled()),
       supports_instant_(false) {
 }
 
 void InstantPage::SetContents(content::WebContents* contents) {
+  if (extended_enabled_ && web_contents())
+    GetSearchModel()->RemoveObserver(this);
+
   Observe(contents);
+
+  if (extended_enabled_ && contents) {
+    SearchModel* model = GetSearchModel();
+    model->AddObserver(this);
+
+    // Already know whether the page supports instant.
+    if (model->instant_support() != INSTANT_SUPPORT_UNKNOWN)
+      SetSupportsInstant(model->instant_support() == INSTANT_SUPPORT_YES);
+  }
 }
 
 bool InstantPage::ShouldProcessRenderViewCreated() {
@@ -152,7 +170,9 @@ void InstantPage::DidFinishLoad(
     const GURL& /* validated_url */,
     bool is_main_frame,
     content::RenderViewHost* /* render_view_host */) {
-  if (is_main_frame && !supports_instant_)
+  // For Instant Extended, SearchTabHelper keeps track of Instant support.
+  if (!extended_enabled_ &&
+      is_main_frame && !supports_instant_)
     DetermineIfPageSupportsInstant();
 }
 
@@ -193,11 +213,35 @@ void InstantPage::DidCommitProvisionalLoadForFrame(
     delegate_->InstantPageAboutToNavigateMainFrame(contents(), url);
 }
 
+void InstantPage::ModelChanged(const SearchModel::State& old_state,
+                               const SearchModel::State& new_state) {
+  if (old_state.instant_support != new_state.instant_support)
+    SetSupportsInstant(new_state.instant_support == INSTANT_SUPPORT_YES);
+}
+
+SearchModel* InstantPage::GetSearchModel() {
+  return contents() ?
+      SearchTabHelper::FromWebContents(contents())->model() : NULL;
+}
+
+void InstantPage::SetSupportsInstant(bool supports_instant) {
+  // Nothing to do if the page already supports Instant.
+  if (supports_instant_)
+    return;
+
+  supports_instant_ = supports_instant;
+  delegate_->InstantSupportDetermined(contents(), supports_instant);
+
+  // If the page doesn't support Instant, stop listening to it.
+  if (!supports_instant)
+    SetContents(NULL);
+}
+
 void InstantPage::OnSetSuggestions(
     int page_id,
     const std::vector<InstantSuggestion>& suggestions) {
   if (contents()->IsActiveEntry(page_id)) {
-    OnInstantSupportDetermined(page_id, true);
+    SetSupportsInstant(true);
     if (ShouldProcessSetSuggestions())
       delegate_->SetSuggestions(contents(), suggestions);
   }
@@ -205,24 +249,16 @@ void InstantPage::OnSetSuggestions(
 
 void InstantPage::OnInstantSupportDetermined(int page_id,
                                              bool supports_instant) {
-  if (!contents()->IsActiveEntry(page_id) || supports_instant_) {
-    // Nothing to do if the page already supports Instant.
-    return;
-  }
-
-  supports_instant_ = supports_instant;
-  delegate_->InstantSupportDetermined(contents(), supports_instant);
-
-  // If the page doesn't support Instant, stop listening to it.
-  if (!supports_instant)
-    Observe(NULL);
+  // For Instant Extended, SearchTabHelper keeps track of Instant support.
+  if (!extended_enabled_ && contents()->IsActiveEntry(page_id))
+    SetSupportsInstant(supports_instant);
 }
 
 void InstantPage::OnShowInstantOverlay(int page_id,
                                        int height,
                                        InstantSizeUnits units) {
   if (contents()->IsActiveEntry(page_id)) {
-    OnInstantSupportDetermined(page_id, true);
+    SetSupportsInstant(true);
     if (ShouldProcessShowInstantOverlay())
       delegate_->ShowInstantOverlay(contents(), height, units);
   }
@@ -230,7 +266,7 @@ void InstantPage::OnShowInstantOverlay(int page_id,
 
 void InstantPage::OnFocusOmnibox(int page_id, OmniboxFocusState state) {
   if (contents()->IsActiveEntry(page_id)) {
-    OnInstantSupportDetermined(page_id, true);
+    SetSupportsInstant(true);
     if (ShouldProcessFocusOmnibox())
       delegate_->FocusOmnibox(contents(), state);
   }
@@ -241,7 +277,7 @@ void InstantPage::OnSearchBoxNavigate(int page_id,
                                       content::PageTransition transition,
                                       WindowOpenDisposition disposition) {
   if (contents()->IsActiveEntry(page_id)) {
-    OnInstantSupportDetermined(page_id, true);
+    SetSupportsInstant(true);
     if (ShouldProcessNavigateToURL())
       delegate_->NavigateToURL(contents(), url, transition, disposition);
   }