[Experiment] purge-and-suspend

third_party/WebKit/Source/core/page/Page.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc. All Rights Reserved.
  * Copyright (C) 2008 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 33 matching lines @@
 #include "core/page/ChromeClient.h"
 #include "core/page/ContextMenuController.h"
 #include "core/page/DragController.h"
 #include "core/page/FocusController.h"
 #include "core/page/PointerLockController.h"
 #include "core/page/ValidationMessageClient.h"
 #include "core/page/scrolling/ScrollingCoordinator.h"
 #include "core/paint/PaintLayer.h"
 #include "platform/graphics/GraphicsLayer.h"
 #include "platform/plugins/PluginData.h"
-#include "platform/text/CompressibleString.h"
 #include "public/platform/Platform.h"
 
 namespace blink {
 
 // Set of all live pages; includes internal Page objects that are
 // not observable from scripts.
 static Page::PageSet& allPages()
 {
     DEFINE_STATIC_LOCAL(Page::PageSet, allPages, ());
     return allPages;
@@ skipping 58 matching lines @@
     , m_openedByDOM(false)
     , m_tabKeyCyclesThroughElements(true)
     , m_defersLoading(false)
     , m_deviceScaleFactor(1)
     , m_visibilityState(PageVisibilityStateVisible)
     , m_isCursorVisible(true)
 #if ENABLE(ASSERT)
     , m_isPainting(false)
 #endif
     , m_frameHost(FrameHost::create(*this))
-    , m_timerForCompressStrings(this, &Page::compressStrings)
 {
     ASSERT(m_editorClient);
 
     ASSERT(!allPages().contains(this));
     allPages().add(this);
 }
 
 Page::~Page()
 {
     // willBeDestroyed() must be called before Page destruction.
@@ skipping 166 matching lines @@
     for (const Page* page : ordinaryPages()) {
         for (Frame* frame = page->m_mainFrame; frame; frame = frame->tree().traverseNext()) {
             if (frame->isLocalFrame())
                 toLocalFrame(frame)->document()->visitedLinkState().invalidateStyleForLink(linkHash);
         }
     }
 }
 
 void Page::setVisibilityState(PageVisibilityState visibilityState, bool isInitialState)
 {
-    static const double waitingTimeBeforeCompressingString = 10;
-
     if (m_visibilityState == visibilityState)
         return;
     m_visibilityState = visibilityState;
 
     if (!isInitialState)
         notifyPageVisibilityChanged();
 
     if (!isInitialState && m_mainFrame)
         m_mainFrame->didChangeVisibilityState();
-
-    // Compress CompressibleStrings when 10 seconds have passed since the page
-    // went to background.
-    if (m_visibilityState == PageVisibilityStateHidden) {

[esprehn, 2016/08/05 23:00:58]

is this actually enabled today?

[tasak, 2016/08/08 04:47:36]

No, not enabled. I manually applied compressibleString patch.

-        if (!m_timerForCompressStrings.isActive())
-            m_timerForCompressStrings.startOneShot(waitingTimeBeforeCompressingString, BLINK_FROM_HERE);
-    } else if (m_timerForCompressStrings.isActive()) {
-        m_timerForCompressStrings.stop();
-    }
 }
 
 PageVisibilityState Page::visibilityState() const
 {
     return m_visibilityState;
 }
 
 bool Page::isPageVisible() const
 {
     return visibilityState() == PageVisibilityStateVisible;
@@ skipping 120 matching lines @@
     // an event so we keep the frames alive until we are done.
     for (Frame* frame = mainFrame(); frame; frame = frame->tree().traverseNext()) {
         if (frame->isLocalFrame())
             frames.append(toLocalFrame(frame));
     }
 
     for (unsigned i = 0; i < frames.size(); ++i)
         frames[i]->localDOMWindow()->acceptLanguagesChanged();
 }
 
+void Page::purgeMemory()
+{
+    // Ask each frame to purge memory.
+    for (Frame* frame = mainFrame(); frame; frame = frame->tree().traverseNext()) {
+        if (frame->isLocalFrame())
+            toLocalFrame(frame)->purgeMemory();
+    }
+}
+
+void Page::onMemoryPressure()
+{
+    for (Page* page : allPages())
+        page->purgeMemory();
+}
+
 DEFINE_TRACE(Page)
 {
     visitor->trace(m_animator);
     visitor->trace(m_autoscrollController);
     visitor->trace(m_chromeClient);
     visitor->trace(m_dragCaretController);
     visitor->trace(m_dragController);
     visitor->trace(m_focusController);
     visitor->trace(m_contextMenuController);
     visitor->trace(m_pointerLockController);
@@ skipping 36 matching lines @@
         m_scrollingCoordinator->willBeDestroyed();
 
     chromeClient().chromeDestroyed();
     if (m_validationMessageClient)
         m_validationMessageClient->willBeDestroyed();
     m_mainFrame = nullptr;
 
     PageVisibilityNotifier::notifyContextDestroyed();
 }
 
-void Page::compressStrings(Timer<Page>* timer)
-{
-    ASSERT_UNUSED(timer, timer == &m_timerForCompressStrings);
-    if (m_visibilityState == PageVisibilityStateHidden)
-        CompressibleStringImpl::compressAll();
-}
-
 Page::PageClients::PageClients()
     : chromeClient(nullptr)
     , contextMenuClient(nullptr)
     , editorClient(nullptr)
     , spellCheckerClient(nullptr)
 {
 }
 
 Page::PageClients::~PageClients()
 {
 }
 
 template class CORE_TEMPLATE_EXPORT Supplement<Page>;
 
 } // namespace blink