Migrate ChromeOS to base::MemoryPressureMonitor

chrome/browser/chromeos/memory/oom_priority_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/chromeos/memory/oom_priority_manager.h"
 
 #include <algorithm>
 #include <set>
 #include <vector>
 
 #include "ash/multi_profile_uma.h"
 #include "ash/session/session_state_delegate.h"
 #include "ash/shell.h"
 #include "base/bind.h"
 #include "base/bind_helpers.h"
-#include "base/chromeos/memory_pressure_observer_chromeos.h"
 #include "base/command_line.h"
+#include "base/memory/memory_pressure_monitor.h"
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
 #include "base/process/process.h"
 #include "base/strings/string16.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/synchronization/lock.h"
 #include "base/threading/thread.h"
 #include "base/time/time.h"
 #include "build/build_config.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/browser_process_platform_part_chromeos.h"
 #include "chrome/browser/chromeos/memory/low_memory_observer.h"
 #include "chrome/browser/memory_details.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_iterator.h"
 #include "chrome/browser/ui/browser_list.h"
 #include "chrome/browser/ui/host_desktop.h"
 #include "chrome/browser/ui/tab_contents/tab_contents_iterator.h"
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
 #include "chrome/browser/ui/tabs/tab_utils.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/url_constants.h"
 #include "chromeos/chromeos_switches.h"
 #include "content/public/browser/browser_thread.h"
-#include "content/public/browser/memory_pressure_observer.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/notification_types.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/render_widget_host.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/zygote_host_linux.h"
 #include "ui/base/text/bytes_formatting.h"
 
 using base::TimeDelta;
 using base::TimeTicks;
@@ skipping 43 matching lines @@
   // instance and thus only work if |name| is constant.
   base::HistogramBase* counter = base::LinearHistogram::FactoryGet(
       name,
       1,  // Minimum. The 0 bin for underflow is automatically added.
       maximum + 1,  // Ensure bucket size of |maximum| / |bucket_count|.
       bucket_count + 2,  // Account for the underflow and overflow bins.
       base::Histogram::kUmaTargetedHistogramFlag);
   counter->Add(sample);
 }
 
-// Gets the MemoryPressureObserver - if it exists.
-base::MemoryPressureObserverChromeOS* GetMemoryPressureObserver() {
-  return content::GetMemoryPressureObserver();
+// Gets the MemoryPressureMonitor - if it exists.
+base::MemoryPressureMonitorChromeOS* GetMemoryPressureMonitor() {

[Mr4D (OOO till 08-26), 2015/04/13 15:10:51]

Why not using MemoryPressureMonitor as a return value here - and / or even
better eliminate this altogether and use the base::MemoryPressureMonitor::Get()
instead where this is called?

[dmichael (off chromium), 2015/04/13 21:02:15]

Done.

+  return static_cast<base::MemoryPressureMonitorChromeOS*>(
+      base::MemoryPressureMonitor::Get());
 }
 
 }  // namespace
 
 ////////////////////////////////////////////////////////////////////////////////
 // OomMemoryDetails logs details about all Chrome processes during an out-of-
 // memory event in an attempt to identify the culprit, then discards a tab and
 // deletes itself.
 class OomMemoryDetails : public MemoryDetails {
  public:
@@ skipping 53 matching lines @@
     tab_contents_id(0) {
 }
 
 OomPriorityManager::TabStats::~TabStats() {
 }
 
 OomPriorityManager::OomPriorityManager()
     : focused_tab_process_info_(std::make_pair(0, 0)),
       discard_count_(0),
       recent_tab_discard_(false) {
-  // Use the old |LowMemoryObserver| when there is no
-  // |MemoryPressureObserverChromeOS|.
-  if (!GetMemoryPressureObserver())
+  // Use the old |LowMemoryObserver| when there is no |MemoryPressureMonitor|.
+  if (!GetMemoryPressureMonitor())
     low_memory_observer_.reset(new LowMemoryObserver);
 
   registrar_.Add(this,
       content::NOTIFICATION_RENDERER_PROCESS_CLOSED,
       content::NotificationService::AllBrowserContextsAndSources());
   registrar_.Add(this,
       content::NOTIFICATION_RENDERER_PROCESS_TERMINATED,
       content::NotificationService::AllBrowserContextsAndSources());
   registrar_.Add(this,
       content::NOTIFICATION_RENDER_WIDGET_VISIBILITY_CHANGED,
@@ skipping 14 matching lines @@
   if (!recent_tab_discard_timer_.IsRunning()) {
     recent_tab_discard_timer_.Start(
         FROM_HERE,
         TimeDelta::FromSeconds(kRecentTabDiscardIntervalSeconds),
         this,
         &OomPriorityManager::RecordRecentTabDiscard);
   }
   start_time_ = TimeTicks::Now();
   // If a |LowMemoryObserver| exists we use the old system, otherwise we create
   // a |MemoryPressureListener| to listen for memory events.
-  if (low_memory_observer_.get()) {
+  if (low_memory_observer_) {
     low_memory_observer_->Start();
   } else {
-    base::MemoryPressureObserverChromeOS* observer =
-        GetMemoryPressureObserver();
-    if (observer) {
+    base::MemoryPressureMonitorChromeOS* monitor = GetMemoryPressureMonitor();
+    if (monitor) {
       memory_pressure_listener_.reset(new base::MemoryPressureListener(
           base::Bind(&OomPriorityManager::OnMemoryPressure,
                      base::Unretained(this))));
       base::MemoryPressureListener::MemoryPressureLevel level =
-          observer->GetCurrentPressureLevel();
+          monitor->GetCurrentPressureLevel();
       if (level ==
           base::MemoryPressureListener::MEMORY_PRESSURE_LEVEL_CRITICAL) {
         OnMemoryPressure(level);
       }
     }
   }
 }
 
 void OomPriorityManager::Stop() {
   timer_.Stop();
   recent_tab_discard_timer_.Stop();
-  if (low_memory_observer_.get())
+  if (low_memory_observer_)
     low_memory_observer_->Stop();
   else
     memory_pressure_listener_.reset();
 }
 
 std::vector<base::string16> OomPriorityManager::GetTabTitles() {
   TabStatsList stats = GetTabStatsOnUIThread();
   base::AutoLock oom_score_autolock(oom_score_lock_);
   std::vector<base::string16> titles;
   titles.reserve(stats.size());
@@ skipping 249 matching lines @@
 void OomPriorityManager::Observe(int type,
                                  const content::NotificationSource& source,
                                  const content::NotificationDetails& details) {
   base::AutoLock oom_score_autolock(oom_score_lock_);
   switch (type) {
     case content::NOTIFICATION_RENDERER_PROCESS_CLOSED:
     case content::NOTIFICATION_RENDERER_PROCESS_TERMINATED: {
       content::RenderProcessHost* host =
           content::Source<content::RenderProcessHost>(source).ptr();
       oom_score_map_.erase(host->GetID());
-      if (!low_memory_observer_.get()) {
+      if (!low_memory_observer_) {
         // Coming here we know that a renderer was just killed and memory should
         // come back into the pool. However - the memory pressure observer did
         // not yet update its status and therefore we ask it to redo the
         // measurement, calling us again if we have to release more.
         // Note: We do not only accelerate the discarding speed by doing another
         // check in short succession - we also accelerate it because the timer
-        // driven MemoryPressureObserver will continue to produce timed events
-        // on top. So as longer as the cleanup phase takes, as more tabs will
+        // driven MemoryPressureMonitor will continue to produce timed events
+        // on top. So the longer the cleanup phase takes, the more tabs will
         // get discarded in parallel.
-        base::MemoryPressureObserverChromeOS* observer =
-            GetMemoryPressureObserver();
-        if (observer)
-          observer->ScheduleEarlyCheck();
+        base::MemoryPressureMonitorChromeOS* monitor =
+            GetMemoryPressureMonitor();
+        if (monitor)
+          monitor->ScheduleEarlyCheck();
       }
       break;
     }
     case content::NOTIFICATION_RENDER_WIDGET_VISIBILITY_CHANGED: {
       bool visible = *content::Details<bool>(details).ptr();
       if (visible) {
         content::RenderProcessHost* render_host =
             content::Source<content::RenderWidgetHost>(source).ptr()->
             GetProcess();
         focused_tab_process_info_ = std::make_pair(render_host->GetID(),
@@ skipping 170 matching lines @@
   // For the moment we only do something when we reach a critical state.
   if (memory_pressure_level ==
       base::MemoryPressureListener::MEMORY_PRESSURE_LEVEL_CRITICAL) {
     LogMemoryAndDiscardTab();
   }
   // TODO(skuhne): If more memory pressure levels are introduced, we might
   // consider to call PurgeBrowserMemory() before CRITICAL is reached.
 }
 
 }  // namespace chromeos