Revert "Take 2: Preload the visited link db on the file thread if"

This reverts commit r35991 due to a perf regression to New Tab Cold
on Mac.

TBR=thakis

Review URL: http://codereview.chromium.org/545024

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@35997 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 10 insertions, 95 deletions

diff --git a/chrome/browser/profile.cc b/chrome/browser/profile.cc
index fefbc8d..3231ede2 100644
--- a/chrome/browser/profile.cc
+++ b/chrome/browser/profile.cc
@@ -125,87 +125,6 @@ bool HasACacheSubdir(const FilePath &dir) {
 
 }  // namespace
 
-// This helper class owns the VisitedLinkMaster and exposes a way to load it
-// from on the file thread.
-class VisitedLinkCreator
-    : public base::RefCountedThreadSafe<VisitedLinkCreator> {
- public:
-  enum LoadState {
-    NOT_LOADED,
-    FILE_LOAD_FAILED,
-    LOAD_FINISHED
-  };
-
-  explicit VisitedLinkCreator(Profile* profile)
-      : listener_(new VisitedLinkEventListener()),
-        profile_(profile),
-        load_state_(NOT_LOADED) {
-    visited_link_master_.reset(new VisitedLinkMaster(listener_.get(),
-                                                     profile_));
-  }
-
-  // Preload the visited link master on the file thread.
-  void Preload() {
-    DCHECK(ChromeThread::CurrentlyOn(ChromeThread::UI));
-    ChromeThread::PostTask(ChromeThread::FILE, FROM_HERE, NewRunnableMethod(
-        this, &VisitedLinkCreator::LoadBackground));
-  }
-
-  // This method can return NULL if for some reason we can't initialize the
-  // visited link master.
-  VisitedLinkMaster* GetMaster() {
-    DCHECK(ChromeThread::CurrentlyOn(ChromeThread::UI));
-    // Go ahead and try to load the VisitedLink table.  If the data was
-    // preloaded, Load() does nothing.
-    AutoLock l(lock_);
-    if (LOAD_FINISHED != load_state_) {
-      bool success = false;
-      if (FILE_LOAD_FAILED == load_state_) {
-        success = visited_link_master_->InitFromScratch();
-      } else if (NOT_LOADED == load_state_) {
-        // We haven't tried to load from file yet, so go ahead and do that.
-        success = visited_link_master_->Init();
-      }
-
-      if (!success) {
-        NOTREACHED() << "Failed to init visited link master.";
-        visited_link_master_.reset();
-      }
-      load_state_ = LOAD_FINISHED;
-    }
-
-    // We don't need to lock here because after Load() has been called, we
-    // never change vistied_link_master_.
-    return visited_link_master_.get();
-  }
-
- private:
-  // Tries to load the visited link database from the UI thread.
-  void LoadBackground() {
-    DCHECK(ChromeThread::CurrentlyOn(ChromeThread::FILE));
-    AutoLock l(lock_);
-    if (NOT_LOADED != load_state_)
-      return;
-
-    // We only want to try to load the data from a file (it's not thread safe
-    // to InitFromScratch on the file thread).
-    load_state_ = visited_link_master_->InitFromFile() ? LOAD_FINISHED
-                                                       : FILE_LOAD_FAILED;
-  }
-
-  scoped_ptr<VisitedLinkMaster::Listener> listener_;
-  Profile* profile_;
-
-  // This lock protects visited_link_master_ and load_state_.
-  Lock lock_;
-  scoped_ptr<VisitedLinkMaster> visited_link_master_;
-  // Once created_ is true, we can stop trying to create and init the
-  // VisitedLinkMaster.
-  LoadState load_state_;
-
-  DISALLOW_COPY_AND_ASSIGN(VisitedLinkCreator);
-};
-
 // A pointer to the request context for the default profile.  See comments on
 // Profile::GetDefaultRequestContext.
 URLRequestContextGetter* Profile::default_request_context_;
@@ -295,9 +214,7 @@ class OffTheRecordProfileImpl : public Profile,
     return reinterpret_cast<ProfileId>(this);
   }
 
-  virtual FilePath GetPath() {
-    return profile_->GetPath();
-  }
+  virtual FilePath GetPath() { return profile_->GetPath(); }
 
   virtual bool IsOffTheRecord() {
     return true;
@@ -328,8 +245,6 @@ class OffTheRecordProfileImpl : public Profile,
     return NULL;
   }
 
-  virtual void PreloadVisitedLinkMaster() {}
-
   virtual ExtensionsService* GetExtensionsService() {
     return NULL;
   }
@@ -652,6 +567,7 @@ class OffTheRecordProfileImpl : public Profile,
 
 ProfileImpl::ProfileImpl(const FilePath& path)
     : path_(path),
+      visited_link_event_listener_(new VisitedLinkEventListener()),
       extension_devtools_manager_(NULL),
       request_context_(NULL),
       media_request_context_(NULL),
@@ -898,16 +814,15 @@ webkit_database::DatabaseTracker* ProfileImpl::GetDatabaseTracker() {
 }
 
 VisitedLinkMaster* ProfileImpl::GetVisitedLinkMaster() {
-  if (!visited_link_creator_.get())
-    visited_link_creator_ = new VisitedLinkCreator(this);
-  return visited_link_creator_->GetMaster();
-}
-
-void ProfileImpl::PreloadVisitedLinkMaster() {
-  if (!visited_link_creator_.get()) {
-    visited_link_creator_ = new VisitedLinkCreator(this);
-    visited_link_creator_->Preload();
+  if (!visited_link_master_.get()) {
+    scoped_ptr<VisitedLinkMaster> visited_links(
+      new VisitedLinkMaster(visited_link_event_listener_.get(), this));
+    if (!visited_links->Init())
+      return NULL;
+    visited_link_master_.swap(visited_links);
   }
+
+  return visited_link_master_.get();
 }
 
 ExtensionsService* ProfileImpl::GetExtensionsService() {