[Search] Store and recall search terms using NavigationEntry to improve search term extraction

chrome/browser/instant/instant_controller.cc

Index: chrome/browser/instant/instant_controller.cc
diff --git a/chrome/browser/instant/instant_controller.cc b/chrome/browser/instant/instant_controller.cc
index acb9583c85849f88a7e1d93d5ca684c5db1ac6b2..6084061d1fdf59eb081a6c3a70caa6a37a114f7f 100644
--- a/chrome/browser/instant/instant_controller.cc
+++ b/chrome/browser/instant/instant_controller.cc
@@ -165,6 +165,9 @@ bool IsFullHeight(const InstantModel& model) {
 const char* InstantController::kLocalOmniboxPopupURL =
     "chrome://local-omnibox-popup/local-omnibox-popup.html";
 
+// static
+const char* InstantController::kSearchTermsKey = "search_terms";
+
 InstantController::InstantController(chrome::BrowserInstantController* browser,
                                      bool extended_enabled,
                                      bool use_local_preview_only)
@@ -478,6 +481,10 @@ bool InstantController::IsPreviewingSearchResults() const {
           last_suggestion_.behavior == INSTANT_COMPLETE_NEVER);
 }
 
+bool InstantController::IsInstantExtendedSearch() const {
+  return extended_enabled_  && instant_enabled_ && last_match_was_search_;
+}
+
 bool InstantController::CommitIfPossible(InstantCommitType type) {
   if (!extended_enabled_ && !instant_enabled_)
     return false;
@@ -521,35 +528,33 @@ bool InstantController::CommitIfPossible(InstantCommitType type) {
   content::WebContents* preview = loader_->ReleaseContents();
 
   if (extended_enabled_) {
-    // Consider what's happening:
-    //   1. The user has typed a query in the omnibox and committed it (either
-    //      by pressing Enter or clicking on the preview).
-    //   2. We commit the preview to the tab strip, and tell the page.
-    //   3. The page will update the URL hash fragment with the query terms.
-    // After steps 1 and 3, the omnibox will show the query terms. However, if
-    // the URL we are committing at step 2 doesn't already have query terms, it
-    // will flash for a brief moment as a plain URL. So, avoid that flicker by
-    // pretending that the plain URL is actually the typed query terms.
-    // TODO(samarth,beaudoin): Instead of this hack, we should add a new field
-    // to NavigationEntry to keep track of what the correct query, if any, is.
     content::NavigationEntry* entry =
         preview->GetController().GetVisibleEntry();
-    std::string url = entry->GetVirtualURL().spec();
-    if (!google_util::IsInstantExtendedAPIGoogleSearchUrl(url) &&
-        google_util::IsGoogleDomainUrl(url, google_util::ALLOW_SUBDOMAIN,
-                                       google_util::ALLOW_NON_STANDARD_PORTS)) {
-      // Hitting ENTER searches for what the user typed, so use
-      // last_omnibox_text_. Clicking on the overlay commits what is currently
-      // showing, so add in the gray text in that case.
-      std::string query(UTF16ToUTF8(last_omnibox_text_));
-      if (type != INSTANT_COMMIT_PRESSED_ENTER)
-        query += UTF16ToUTF8(last_suggestion_.text);
+    // Adjust the search terms shown in the omnibox for this query. Hitting
+    // ENTER searches for what the user typed, so use last_omnibox_text_.
+    // Clicking on the overlay commits what is currently showing, so add in the
+    // gray text in that case.
+    std::string query(UTF16ToUTF8(last_omnibox_text_));
+    if (type != INSTANT_COMMIT_PRESSED_ENTER)
+      query += UTF16ToUTF8(last_suggestion_.text);
+
+    if (type == INSTANT_COMMIT_CLICKED_QUERY_SUGGESTION ||
+        type == INSTANT_COMMIT_FOCUS_LOST) {
+      // We update the virtual URL's hash fragment to the current omnibox text
+      // to avoid the flash of a URL that may not contain any search terms. The
+      // virtual URL will get reparsed once it is updated by the page to contain
+      // the valid search terms.
       entry->SetVirtualURL(GURL(
-          url + "#q=" +
+          entry->GetVirtualURL().spec() + "#q=" +
           net::EscapeQueryParamValue(query, true)));
-      chrome::search::SearchTabHelper::FromWebContents(preview)->
-          NavigationEntryUpdated();
+    } else {
+      // The search terms contained in |query| are valid and should be
+      // persisted, with no need to be reparsed.
+      entry->SetExtraData(std::string(kSearchTermsKey), UTF8ToUTF16(query));
     }
+
+    chrome::search::SearchTabHelper::FromWebContents(preview)->
+        NavigationEntryUpdated();
   }
 
   // If the preview page has navigated since the last Update(), we need to add