Omnibox: Add Field Trial to Create UWYT When Inlining

chrome/browser/autocomplete/history_url_provider.h

 // 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_AUTOCOMPLETE_HISTORY_URL_PROVIDER_H_
 #define CHROME_BROWSER_AUTOCOMPLETE_HISTORY_URL_PROVIDER_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 138 matching lines @@
   // Tells the provider whether to promote the what you typed match, the first
   // element of |matches|, or neither as the first AutocompleteMatch.  If
   // |exact_suggestion_is_in_history| is true (and thus "the what you typed
   // match" and "the first element of |matches|" represent the same thing), this
   // will be set to WHAT_YOU_TYPED_MATCH.
   //
   // NOTE: The second pass of DoAutocomplete() checks what the first pass set
   // this to.  See comments in DoAutocomplete().
   PromoteType promote_type;
 
+  // True if we should consider adding the what you typed match.  This
+  // decision is often already summarized in |promote_type| by whether it
+  // says to promote the what you typed match.  As such, this variable is
+  // only useful when |promote_type| is FRONT_HISTORY_MATCH.

[Peter Kasting, 2014/06/20 21:12:42]

Nit: I think this comment would be clearer as:

True if |what_you_typed_match| is eligible for display.  If this is true,
PromoteMatchesIfNecessary() may choose to place |what_you_typed_match| on
|matches_| even when |promote_type| is not WHAT_YOU_TYPED_MATCH.

[Mark P, 2014/06/23 22:23:12]

Yes, that is clearer.  Done.

+  bool have_what_you_typed_match;
+
   // Languages we should pass to gfx::GetCleanStringFromUrl.
   std::string languages;
 
   // The default search provider and search terms data necessary to cull results
   // that correspond to searches (on the default engine).  These can only be
   // obtained on the UI thread, so we have to copy them into here to pass them
   // to the history thread.  We use a scoped_ptr<TemplateURL> for the DSP since
   // TemplateURLs can't be copied by value. We use a scoped_ptr<SearchTermsData>
   // so that we can store a snapshot of the SearchTermsData accessible from the
   // history thread.
@@ skipping 69 matching lines @@
 
   // Actually runs the autocomplete job on the given database, which is
   // guaranteed not to be NULL.  Used by both autocomplete passes, and therefore
   // called on multiple different threads (though not simultaneously).
   void DoAutocomplete(history::HistoryBackend* backend,
                       history::URLDatabase* db,
                       HistoryURLProviderParams* params);
 
   // May promote either the what you typed match or first history match in
   // params->matches to the front of |matches_|, depending on the value of
-  // params->promote_type.
-  void PromoteMatchIfNecessary(const HistoryURLProviderParams& params);
+  // params->promote_type.  Also, depending on a field trial state, if it
+  // promotes the first history match, it may decide to append the what you
+  // typed matche immediately after.

[Peter Kasting, 2014/06/20 21:12:42]

Nit: How about:

May promote the what you typed match, the first history match, or both to the
front of |matches_|, depending on the values of params->promote_type and
params->have_what_you_typed_match.

(I don't think we need to mention field trial state here as this isn't meant to
be an exhaustive guide, but if you want to, you could add ", as well as field
trial state." to the end.)

[Mark P, 2014/06/23 22:23:12]

Okay, omitting the mention of the field trial seems reasonable.  Took your
comment with a minor edit (to mention params->matches).

+  void PromoteMatchesIfNecessary(const HistoryURLProviderParams& params);
 
   // Dispatches the results to the autocomplete controller. Called on the
   // main thread by ExecuteWithDB when the results are available.
   // Frees params_gets_deleted on exit.
   void QueryComplete(HistoryURLProviderParams* params_gets_deleted);
 
   // Looks up the info for params->what_you_typed_match in the DB.  If found,
   // fills in the title, promotes the match's priority to that of an inline
   // autocomplete match (maybe it should be slightly better?), and places it on
   // the front of params->matches (so we pick the right matches to throw away
@@ skipping 76 matching lines @@
   // Used in PromoteOrCreateShorterSuggestion().  If true, we may create
   // shorter suggestions even when they haven't been visited before:
   // if the user visited http://example.com/asdf once, we'll suggest
   // http://example.com/ even if they've never been to it.
   bool create_shorter_match_;
 
   DISALLOW_COPY_AND_ASSIGN(HistoryURLProvider);
 };
 
 #endif  // CHROME_BROWSER_AUTOCOMPLETE_HISTORY_URL_PROVIDER_H_