IndexedDB: Remove UMA collection for total database open time

These metrics were added here: https://crrev.com/470373002

From a review of whether we use this today, these are no longer
used/needed.

Bug: 717812, 397552, 395799
Change-Id: I1b296832a7ed87fb9653be9eb83cc2b3eb8ef6b1
Reviewed-on: https://chromium-review.googlesource.com/c/1336429
Commit-Queue: Chase Phillips <cmp@chromium.org>
Reviewed-by: Steven Holte <holte@chromium.org>
Reviewed-by: Victor Costan <pwnall@chromium.org>
Reviewed-by: Chris Mumford <cmumford@chromium.org>
Cr-Commit-Position: refs/heads/master@{#608613}

content/browser/indexed_db/indexed_db_callbacks.cc

@@ -11,7 +11,6 @@
 #include <utility>
 
 #include "base/guid.h"
-#include "base/metrics/histogram_macros.h"
 #include "base/sequenced_task_runner.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/task/post_task.h"
@@ -243,13 +242,6 @@ void IndexedDBCallbacks::OnError(const IndexedDBDatabaseError& error) {
       base::BindOnce(&IOThreadHelper::SendError,
                      base::Unretained(io_helper_.get()), error));
   complete_ = true;
-
-  if (!connection_open_start_time_.is_null()) {
-    UMA_HISTOGRAM_MEDIUM_TIMES(
-        "WebCore.IndexedDB.OpenTime.Error",
-        base::TimeTicks::Now() - connection_open_start_time_);
-    connection_open_start_time_ = base::TimeTicks();
-  }
 }
 
 void IndexedDBCallbacks::OnSuccess(
@@ -292,13 +284,6 @@ void IndexedDBCallbacks::OnBlocked(int64_t existing_version) {
       FROM_HERE, {BrowserThread::IO},
       base::BindOnce(&IOThreadHelper::SendBlocked,
                      base::Unretained(io_helper_.get()), existing_version));
-
-  if (!connection_open_start_time_.is_null()) {
-    UMA_HISTOGRAM_MEDIUM_TIMES(
-        "WebCore.IndexedDB.OpenTime.Blocked",
-        base::TimeTicks::Now() - connection_open_start_time_);
-    connection_open_start_time_ = base::TimeTicks();
-  }
 }
 
 void IndexedDBCallbacks::OnUpgradeNeeded(
@@ -322,13 +307,6 @@ void IndexedDBCallbacks::OnUpgradeNeeded(
                      base::Unretained(io_helper_.get()), std::move(wrapper),
                      old_version, data_loss_info.status, data_loss_info.message,
                      metadata));
-
-  if (!connection_open_start_time_.is_null()) {
-    UMA_HISTOGRAM_MEDIUM_TIMES(
-        "WebCore.IndexedDB.OpenTime.UpgradeNeeded",
-        base::TimeTicks::Now() - connection_open_start_time_);
-    connection_open_start_time_ = base::TimeTicks();
-  }
 }
 
 void IndexedDBCallbacks::OnSuccess(
@@ -354,13 +332,6 @@ void IndexedDBCallbacks::OnSuccess(
                                           base::Unretained(io_helper_.get()),
                                           std::move(wrapper), metadata));
   complete_ = true;
-
-  if (!connection_open_start_time_.is_null()) {
-    UMA_HISTOGRAM_MEDIUM_TIMES(
-        "WebCore.IndexedDB.OpenTime.Success",
-        base::TimeTicks::Now() - connection_open_start_time_);
-    connection_open_start_time_ = base::TimeTicks();
-  }
 }
 
 void IndexedDBCallbacks::OnSuccess(std::unique_ptr<IndexedDBCursor> cursor,
@@ -519,11 +490,6 @@ void IndexedDBCallbacks::OnSuccess() {
   complete_ = true;
 }
 
-void IndexedDBCallbacks::SetConnectionOpenStartTime(
-    const base::TimeTicks& start_time) {
-  connection_open_start_time_ = start_time;
-}
-
 IndexedDBCallbacks::IOThreadHelper::IOThreadHelper(
     IDBCallbacksAssociatedPtrInfo callbacks_info,
     base::WeakPtr<IndexedDBDispatcherHost> dispatcher_host,

content/browser/indexed_db/indexed_db_callbacks.h

@@ -106,8 +106,6 @@ class CONTENT_EXPORT IndexedDBCallbacks
   // IndexedDBCursor::Continue / Advance (when complete)
   virtual void OnSuccess();
 
-  void SetConnectionOpenStartTime(const base::TimeTicks& start_time);
-
  protected:
   virtual ~IndexedDBCallbacks();
 
@@ -129,7 +127,6 @@ class CONTENT_EXPORT IndexedDBCallbacks
 
   // The "blocked" event should be sent at most once per request.
   bool sent_blocked_ = false;
-  base::TimeTicks connection_open_start_time_;
 
   std::unique_ptr<IOThreadHelper, BrowserThread::DeleteOnIOThread> io_helper_;
   SEQUENCE_CHECKER(sequence_checker_);

content/browser/indexed_db/indexed_db_dispatcher_host.cc

@@ -331,12 +331,10 @@ void IndexedDBDispatcherHost::IDBSequenceHelper::OpenOnIDBThread(
     int64_t transaction_id) {
   DCHECK(indexed_db_context_->TaskRunner()->RunsTasksInCurrentSequence());
 
-  base::TimeTicks begin_time = base::TimeTicks::Now();
   base::FilePath indexed_db_path = indexed_db_context_->data_path();
 
   // TODO(dgrogan): Don't let a non-existing database be opened (and therefore
   // created) if this origin is already over quota.
-  callbacks->SetConnectionOpenStartTime(begin_time);
   std::unique_ptr<IndexedDBPendingConnection> connection =
       std::make_unique<IndexedDBPendingConnection>(
           callbacks, database_callbacks, ipc_process_id_, transaction_id,

tools/metrics/histograms/histograms.xml

@@ -120632,6 +120632,9 @@ uploading your change for review.
 </histogram>
 
 <histogram name="WebCore.IndexedDB.OpenTime.Blocked" units="ms">
+  <obsolete>
+    Deprecated 2018-11. No longer needed.
+  </obsolete>
   <owner>cmumford@chromium.org</owner>
   <summary>
     The delay between the receipt of the request to open an IndexedDB database
@@ -120640,6 +120643,9 @@ uploading your change for review.
 </histogram>
 
 <histogram name="WebCore.IndexedDB.OpenTime.Error" units="ms">
+  <obsolete>
+    Deprecated 2018-11. No longer needed.
+  </obsolete>
   <owner>cmumford@chromium.org</owner>
   <summary>
     The delay between the receipt of the request to open an IndexedDB database
@@ -120648,6 +120654,9 @@ uploading your change for review.
 </histogram>
 
 <histogram name="WebCore.IndexedDB.OpenTime.Success" units="ms">
+  <obsolete>
+    Deprecated 2018-11. No longer needed.
+  </obsolete>
   <owner>cmumford@chromium.org</owner>
   <summary>
     The delay between the receipt of the request to open an IndexedDB database
@@ -120656,6 +120665,9 @@ uploading your change for review.
 </histogram>
 
 <histogram name="WebCore.IndexedDB.OpenTime.UpgradeNeeded" units="ms">
+  <obsolete>
+    Deprecated 2018-11. No longer needed.
+  </obsolete>
   <owner>cmumford@chromium.org</owner>
   <summary>
     The delay between the receipt of the request to open an IndexedDB database