Stop suspending renderer and changing purge interval to 20min

chrome/browser/memory/tab_manager.cc

 // 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.
 
 #include "chrome/browser/memory/tab_manager.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <set>
@@ skipping 68 matching lines @@
 // Tabs.Discard.DiscardInLastMinute must be replaced with a new statistic.
 const int kRecentTabDiscardIntervalSeconds = 60;
 #endif
 
 // If there has been no priority adjustment in this interval, assume the
 // machine was suspended and correct the timing statistics.
 const int kSuspendThresholdSeconds = kAdjustmentIntervalSeconds * 4;
 
 // A suspended renderer is suspended for this duration.
 constexpr base::TimeDelta kDurationOfRendererSuspension =
-    base::TimeDelta::FromSeconds(120);
+    base::TimeDelta::FromSeconds(1200);

[bashi, 2017/01/13 02:11:42]

We no longer suspend renderers. Shouldn't we change the name of this const and
related flags? I understand the cost of renaming as it affects a lot of things
including experiments, but I'd prefer avoiding confusions.

I think it's fine to rename this in follow-up CLs.

[tasak, 2017/01/13 03:27:04]

Acknowledged.
But currelty it is difficult to rename this, because there is no way to purge
cache except changing MC state from NORMAL to SUSPENDED.

[bashi, 2017/01/13 04:36:23]

Yeah, currently it's difficult to rename as purging is depend on
MemoryCoordinatorClient::OnMemoryStateChange(). However at least we should stop
using "suspend" outside memory coordinator (and clients). We can rename
variables and functions in RenderThreadImpl. (Though we still call
base::MemoryCoordinatorClientRegistry::GetInstance()->Notify(base::MemoryState::SUSPENDED)).

 
 // A resumed renderer is resumed for this duration.
 constexpr base::TimeDelta kDurationOfRendererResumption =
     base::TimeDelta::FromSeconds(10);
 
 // The time during which a tab is protected from discarding after it stops being
 // audible.
 const int kAudioProtectionTimeSeconds = 60;
 
 int FindTabStripModelById(int64_t target_web_contents_id,
@@ skipping 928 matching lines @@
   // platform.
   std::string allow_multiple_discards = variations::GetVariationParamValue(
       features::kAutomaticTabDiscarding.name, "AllowMultipleDiscards");
   return (allow_multiple_discards != "true");
 #else
   return false;
 #endif
 }
 
 }  // namespace memory