Revert of Revert of Componentize HistoryURLProvider/ScoredHistoryMatch.

chrome/browser/autocomplete/history_url_provider.h

Index: chrome/browser/autocomplete/history_url_provider.h
diff --git a/chrome/browser/autocomplete/history_url_provider.h b/chrome/browser/autocomplete/history_url_provider.h
deleted file mode 100644
index 53796f45f3bb6c759eb5cac84fdb0023fb40eaaa..0000000000000000000000000000000000000000
--- a/chrome/browser/autocomplete/history_url_provider.h
+++ /dev/null
@@ -1,344 +0,0 @@
-// 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>
-
-#include "base/compiler_specific.h"
-#include "base/synchronization/cancellation_flag.h"
-#include "base/threading/thread_checker.h"
-#include "components/history/core/browser/history_match.h"
-#include "components/omnibox/autocomplete_input.h"
-#include "components/omnibox/history_provider.h"
-#include "components/omnibox/omnibox_field_trial.h"
-#include "components/search_engines/template_url.h"
-
-class AutocompleteProviderListener;
-class SearchTermsData;
-
-namespace base {
-class MessageLoop;
-}
-
-namespace history {
-class HistoryBackend;
-class URLDatabase;
-}
-
-// How history autocomplete works
-// ==============================
-//
-// Read down this diagram for temporal ordering.
-//
-//   Main thread                History thread
-//   -----------                --------------
-//   AutocompleteController::Start
-//     -> HistoryURLProvider::Start
-//       -> SuggestExactInput
-//       [params_ allocated]
-//       -> DoAutocomplete (for inline autocomplete)
-//         -> URLDatabase::AutocompleteForPrefix (on in-memory DB)
-//       -> HistoryService::ScheduleAutocomplete
-//       (return to controller) ----
-//                                 /
-//                            HistoryBackend::ScheduleAutocomplete
-//                              -> HistoryURLProvider::ExecuteWithDB
-//                                -> DoAutocomplete
-//                                  -> URLDatabase::AutocompleteForPrefix
-//                              /
-//   HistoryService::QueryComplete
-//     [params_ destroyed]
-//     -> AutocompleteProviderListener::OnProviderUpdate
-//
-// The autocomplete controller calls us, and must be called back, on the main
-// thread.  When called, we run two autocomplete passes.  The first pass runs
-// synchronously on the main thread and queries the in-memory URL database.
-// This pass promotes matches for inline autocomplete if applicable.  We do
-// this synchronously so that users get consistent behavior when they type
-// quickly and hit enter, no matter how loaded the main history database is.
-// Doing this synchronously also prevents inline autocomplete from being
-// "flickery" in the AutocompleteEdit.  Because the in-memory DB does not have
-// redirect data, results other than the top match might change between the
-// two passes, so we can't just decide to use this pass' matches as the final
-// results.
-//
-// The second autocomplete pass uses the full history database, which must be
-// queried on the history thread.  Start() asks the history service schedule to
-// callback on the history thread with a pointer to the main database.  When we
-// are done doing queries, we schedule a task on the main thread that notifies
-// the AutocompleteController that we're done.
-//
-// The communication between these threads is done using a
-// HistoryURLProviderParams object.  This is allocated in the main thread, and
-// normally deleted in QueryComplete().  So that both autocomplete passes can
-// use the same code, we also use this to hold results during the first
-// autocomplete pass.
-//
-// While the second pass is running, the AutocompleteController may cancel the
-// request.  This can happen frequently when the user is typing quickly.  In
-// this case, the main thread sets params_->cancel, which the background thread
-// checks periodically.  If it finds the flag set, it stops what it's doing
-// immediately and calls back to the main thread.  (We don't delete the params
-// on the history thread, because we should only do that when we can safely
-// NULL out params_, and that must be done on the main thread.)
-
-// Used to communicate autocomplete parameters between threads via the history
-// service.
-struct HistoryURLProviderParams {
-  // See comments on |promote_type| below.
-  enum PromoteType {
-    WHAT_YOU_TYPED_MATCH,
-    FRONT_HISTORY_MATCH,
-    NEITHER,
-  };
-
-  HistoryURLProviderParams(const AutocompleteInput& input,
-                           bool trim_http,
-                           const AutocompleteMatch& what_you_typed_match,
-                           const std::string& languages,
-                           TemplateURL* default_search_provider,
-                           const SearchTermsData& search_terms_data);
-  ~HistoryURLProviderParams();
-
-  base::MessageLoop* message_loop;
-
-  // A copy of the autocomplete input. We need the copy since this object will
-  // live beyond the original query while it runs on the history thread.
-  AutocompleteInput input;
-
-  // Should inline autocompletion be disabled? This is initalized from
-  // |input.prevent_inline_autocomplete()|, but set to false is the input
-  // contains trailing white space.
-  bool prevent_inline_autocomplete;
-
-  // Set when "http://" should be trimmed from the beginning of the URLs.
-  bool trim_http;
-
-  // A match corresponding to what the user typed.
-  AutocompleteMatch what_you_typed_match;
-
-  // Set by the main thread to cancel this request.  If this flag is set when
-  // the query runs, the query will be abandoned.  This allows us to avoid
-  // running queries that are no longer needed.  Since we don't care if we run
-  // the extra queries, the lack of signaling is not a problem.
-  base::CancellationFlag cancel_flag;
-
-  // Set by ExecuteWithDB() on the history thread when the query could not be
-  // performed because the history system failed to properly init the database.
-  // If this is set when the main thread is called back, it avoids changing
-  // |matches_| at all, so it won't delete the default match Start() creates.
-  bool failed;
-
-  // List of matches written by DoAutocomplete().  Upon its return the provider
-  // converts this list to ACMatches and places them in |matches_|.
-  history::HistoryMatches matches;
-
-  // True if the suggestion for exactly what the user typed appears as a known
-  // URL in the user's history.  In this case, this will also be the first match
-  // in |matches|.
-  //
-  // NOTE: There are some complications related to keeping things consistent
-  // between passes and how we deal with intranet URLs, which are too complex to
-  // explain here; see the implementations of DoAutocomplete() and
-  // FixupExactSuggestion() for specific comments.
-  bool exact_suggestion_is_in_history;
-
-  // 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 |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.
-  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.
-  scoped_ptr<TemplateURL> default_search_provider;
-  scoped_ptr<SearchTermsData> search_terms_data;
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(HistoryURLProviderParams);
-};
-
-// This class is an autocomplete provider and is also a pseudo-internal
-// component of the history system.  See comments above.
-class HistoryURLProvider : public HistoryProvider {
- public:
-  // Various values used in scoring, made public so other providers
-  // can insert results in appropriate ranges relative to these.
-  static const int kScoreForBestInlineableResult;
-  static const int kScoreForUnvisitedIntranetResult;
-  static const int kScoreForWhatYouTypedResult;
-  static const int kBaseScoreForNonInlineableResult;
-
-  HistoryURLProvider(AutocompleteProviderClient* client,
-                     AutocompleteProviderListener* listener);
-
-  // HistoryProvider:
-  void Start(const AutocompleteInput& input,
-             bool minimal_changes,
-             bool called_due_to_focus) override;
-  void Stop(bool clear_cached_results, bool due_to_user_inactivity) override;
-
-  // Returns a match representing a navigation to |destination_url| given user
-  // input of |text|.  |trim_http| controls whether the match's |fill_into_edit|
-  // and |contents| should have any HTTP scheme stripped off, and should not be
-  // set to true if |text| contains an http prefix.
-  // NOTES: This does not set the relevance of the returned match, as different
-  //        callers want different behavior. Callers must set this manually.
-  //        This function should only be called on the UI thread.
-  AutocompleteMatch SuggestExactInput(const base::string16& text,
-                                      const GURL& destination_url,
-                                      bool trim_http);
-
-  // Runs the history query on the history thread, called by the history
-  // system. The history database MAY BE NULL in which case it is not
-  // available and we should return no data. Also schedules returning the
-  // results to the main thread
-  void ExecuteWithDB(HistoryURLProviderParams* params,
-                     history::HistoryBackend* backend,
-                     history::URLDatabase* db);
-
- private:
-  FRIEND_TEST_ALL_PREFIXES(HistoryURLProviderTest, HUPScoringExperiment);
-
-  enum MatchType {
-    NORMAL,
-    WHAT_YOU_TYPED,
-    INLINE_AUTOCOMPLETE,
-    UNVISITED_INTRANET,  // An intranet site that has never been visited.
-  };
-  class VisitClassifier;
-
-  ~HistoryURLProvider() override;
-
-  // Determines the relevance for a match, given its type.  If |match_type| is
-  // NORMAL, |match_number| is a number indicating the relevance of the match
-  // (higher == more relevant).  For other values of |match_type|,
-  // |match_number| is ignored.  Only called some of the time; for some matches,
-  // relevancy scores are assigned consecutively decreasing (1416, 1415, ...).
-  static int CalculateRelevance(MatchType match_type, int match_number);
-
-  // Returns a set of classifications that highlight all the occurrences of
-  // |input_text| at word breaks in |description|.
-  static ACMatchClassifications ClassifyDescription(
-      const base::string16& input_text,
-      const base::string16& description);
-
-  // 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 the what you typed match, the first history match in
-  // params->matches, or both to the front of |matches_|, depending on the
-  // values of params->promote_type, params->have_what_you_typed_match, and
-  // params->prevent_inline_autocomplete.
-  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
-  // when culling redirects to/from it).  Returns whether a match was promoted.
-  bool FixupExactSuggestion(history::URLDatabase* db,
-                            const VisitClassifier& classifier,
-                            HistoryURLProviderParams* params) const;
-
-  // Helper function for FixupExactSuggestion, this returns true if the input
-  // corresponds to some intranet URL where the user has previously visited the
-  // host in question.  In this case the input should be treated as a URL.
-  bool CanFindIntranetURL(history::URLDatabase* db,
-                          const AutocompleteInput& input) const;
-
-  // Sees if a shorter version of the best match should be created, and if so
-  // places it at the front of params->matches.  This can suggest history URLs
-  // that are prefixes of the best match (if they've been visited enough,
-  // compared to the best match), or create host-only 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.
-  // Returns true if a match was successfully created/promoted that we're
-  // willing to inline autocomplete.
-  bool PromoteOrCreateShorterSuggestion(
-      history::URLDatabase* db,
-      HistoryURLProviderParams* params);
-
-  // Removes results that have been rarely typed or visited, and not any time
-  // recently.  The exact parameters for this heuristic can be found in the
-  // function body. Also culls results corresponding to queries from the default
-  // search engine. These are low-quality, difficult-to-understand matches for
-  // users, and the SearchProvider should surface past queries in a better way
-  // anyway.
-  void CullPoorMatches(HistoryURLProviderParams* params) const;
-
-  // Removes results that redirect to each other, leaving at most |max_results|
-  // results.
-  void CullRedirects(history::HistoryBackend* backend,
-                     history::HistoryMatches* matches,
-                     size_t max_results) const;
-
-  // Helper function for CullRedirects, this removes all but the first
-  // occurance of [any of the set of strings in |remove|] from the |matches|
-  // list.
-  //
-  // The return value is the index of the item that is after the item in the
-  // input identified by |source_index|. If |source_index| or an item before
-  // is removed, the next item will be shifted, and this allows the caller to
-  // pick up on the next one when this happens.
-  size_t RemoveSubsequentMatchesOf(history::HistoryMatches* matches,
-                                   size_t source_index,
-                                   const std::vector<GURL>& remove) const;
-
-  // Converts a specified |match_number| from params.matches into an
-  // autocomplete match for display.  If experimental scoring is enabled, the
-  // final relevance score might be different from the given |relevance|.
-  // NOTE: This function should only be called on the UI thread.
-  AutocompleteMatch HistoryMatchToACMatch(
-      const HistoryURLProviderParams& params,
-      size_t match_number,
-      MatchType match_type,
-      int relevance);
-
-  AutocompleteProviderListener* listener_;
-
-  // Params for the current query.  The provider should not free this directly;
-  // instead, it is passed as a parameter through the history backend, and the
-  // parameter itself is freed once it's no longer needed.  The only reason we
-  // keep this member is so we can set the cancel bit on it.
-  HistoryURLProviderParams* params_;
-
-  // Params controlling experimental behavior of this provider.
-  HUPScoringParams scoring_params_;
-
-  base::ThreadChecker thread_checker_;
-
-  DISALLOW_COPY_AND_ASSIGN(HistoryURLProvider);
-};
-
-#endif  // CHROME_BROWSER_AUTOCOMPLETE_HISTORY_URL_PROVIDER_H_