[Experiment] purge-and-suspend

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

Index: third_party/WebKit/Source/core/page/Page.cpp
diff --git a/third_party/WebKit/Source/core/page/Page.cpp b/third_party/WebKit/Source/core/page/Page.cpp
index ff71fae0c65ade2aa799053f8718ba2b8a3e55f3..99ac3a5af71e51c78942878899ac65603c1dd8f3 100644
--- a/third_party/WebKit/Source/core/page/Page.cpp
+++ b/third_party/WebKit/Source/core/page/Page.cpp
@@ -49,7 +49,6 @@
 #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 {
@@ -128,7 +127,6 @@ Page::Page(PageClients& pageClients)
     , m_isPainting(false)
 #endif
     , m_frameHost(FrameHost::create(*this))
-    , m_timerForCompressStrings(this, &Page::compressStrings)
 {
     ASSERT(m_editorClient);
 
@@ -315,8 +313,6 @@ void Page::visitedStateChanged(LinkHash linkHash)
 
 void Page::setVisibilityState(PageVisibilityState visibilityState, bool isInitialState)
 {
-    static const double waitingTimeBeforeCompressingString = 10;
-
     if (m_visibilityState == visibilityState)
         return;
     m_visibilityState = visibilityState;
@@ -326,15 +322,6 @@ void Page::setVisibilityState(PageVisibilityState visibilityState, bool isInitia
 
     if (!isInitialState && m_mainFrame)
         m_mainFrame->didChangeVisibilityState();
-
-    // Compress CompressibleStrings when 10 seconds have passed since the page
-    // went to background.
-    if (m_visibilityState == PageVisibilityStateHidden) {
-        if (!m_timerForCompressStrings.isActive())
-            m_timerForCompressStrings.startOneShot(waitingTimeBeforeCompressingString, BLINK_FROM_HERE);
-    } else if (m_timerForCompressStrings.isActive()) {
-        m_timerForCompressStrings.stop();
-    }
 }
 
 PageVisibilityState Page::visibilityState() const
@@ -461,6 +448,21 @@ void Page::acceptLanguagesChanged()
         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);
@@ -517,13 +519,6 @@ void Page::willBeDestroyed()
     PageLifecycleNotifier::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)