Move instant support to SearchTabHelper.

chrome/browser/ui/search/instant_controller.cc

 // Copyright 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/instant_controller.h"
 
 #include <iterator>
 
 #include "base/metrics/histogram.h"
 #include "base/string_util.h"
@@ skipping 953 matching lines @@
     return;
 
   LOG_INSTANT_DEBUG_EVENT(this, base::StringPrintf(
       "SearchModeChanged: [origin:mode] %d:%d to %d:%d", old_mode.origin,
       old_mode.mode, new_mode.origin, new_mode.mode));
 
   search_mode_ = new_mode;
   if (!new_mode.is_search_suggestions())
     HideOverlay();
 
-  ResetInstantTab();
+  // Now that the overlay is hidden, try |instant_tab_| again.

[samarth, 2013/05/08 02:38:48]

Let's take out all the instant tab resetting logic out of this CL and focus on
the instant support determined bit.

[kmadhusu, 2013/05/09 02:40:40]

Done.

+  if (!instant_tab_)
+    ResetInstantTab();
 }
 
 void InstantController::ActiveTabChanged() {
   if (!extended_enabled_ && !instant_enabled_)
     return;
 
   LOG_INSTANT_DEBUG_EVENT(this, "ActiveTabChanged");
 
   // When switching tabs, always hide the overlay.
   HideOverlay();
@@ skipping 531 matching lines @@
 
 void InstantController::ResetInstantTab() {
   // Do not wire up the InstantTab in Incognito, to prevent it from sending data
   // to the page.
   if (!search_mode_.is_origin_default() &&
       !browser_->profile()->IsOffTheRecord()) {
     content::WebContents* active_tab = browser_->GetActiveWebContents();
     if (!instant_tab_ || active_tab != instant_tab_->contents()) {
       instant_tab_.reset(new InstantTab(this));
       instant_tab_->Init(active_tab);
-      UpdateInfoForInstantTab();
-      use_tab_for_suggestions_ = true;
+      // Note that |instant_tab_| may have gotten reset in Init() if it's
+      // already known to not support instant.
+      if (instant_tab_) {
+        UpdateInfoForInstantTab();
+        use_tab_for_suggestions_ = true;
+      } else {
+        use_tab_for_suggestions_ = false;
+      }
     }
 
-    // Hide the |overlay_| since we are now using |instant_tab_| instead.
-    HideOverlay();
+    if (instant_tab_) {
+      // Hide the |overlay_| since we are now using |instant_tab_| instead.
+      HideOverlay();
+    }
   } else {
     instant_tab_.reset();
   }
 }
 
 void InstantController::UpdateInfoForInstantTab() {
   if (instant_tab_) {
     browser_->UpdateThemeInfo();
     instant_tab_->SetDisplayInstantResults(instant_enabled_);
     instant_tab_->SetOmniboxBounds(omnibox_bounds_);
@@ skipping 40 matching lines @@
       "Show: height=%d units=%d", height, units));
 
   // Must have updated omnibox after the last HideOverlay() to show suggestions.
   if (!allow_overlay_to_show_search_suggestions_)
     return;
 
   // The page is trying to hide itself. Hide explicitly (i.e., don't use
   // HideOverlay()) so that it can change its mind.
   if (height == 0) {
     model_.SetOverlayState(SearchMode(), 0, INSTANT_SIZE_PERCENT);
-    if (instant_tab_)
+    if (instant_tab_) {
       use_tab_for_suggestions_ = true;
+    } else {
+      // Now that the overlay is hidden, try |instant_tab_| again.
+      ResetInstantTab();
+    }
     return;
   }
 
   // If the overlay is being shown for the first time since the user started
   // typing, record a histogram value.
   if (!first_interaction_time_.is_null() && model_.mode().is_default()) {
     base::TimeDelta delta = base::Time::Now() - first_interaction_time_;
     UMA_HISTOGRAM_TIMES("Instant.TimeToFirstShow", delta);
   }
 
@@ skipping 202 matching lines @@
 
   result->transition = match.transition;
   result->relevance = match.relevance;
   result->autocomplete_match_index = autocomplete_match_index;
 
   DVLOG(1) << "    " << result->relevance << " " << result->type << " "
       << result->provider << " " << result->destination_url << " '"
       << result->description << "' '" << result->search_query << "' "
       << result->transition <<  " " << result->autocomplete_match_index;
 }