Experimental CompressibleString UMA

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 6ed312c28645668efdf089e6a98768aae7dbaed9..c587b9c432764e6330589cf8235ef912fcdad5e3 100644
--- a/third_party/WebKit/Source/core/page/Page.cpp
+++ b/third_party/WebKit/Source/core/page/Page.cpp
@@ -50,6 +50,7 @@
 #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 {
@@ -136,6 +137,7 @@ Page::Page(PageClients& pageClients)
     , m_isPainting(false)
 #endif
     , m_frameHost(FrameHost::create(*this))
+    , m_timerForCompressStrings(this, &Page::compressStrings)
 {
     ASSERT(m_editorClient);
 
@@ -363,6 +365,9 @@ void Page::visitedStateChanged(LinkHash linkHash)
 
 void Page::setVisibilityState(PageVisibilityState visibilityState, bool isInitialState)
 {
+    static const double waitingTimeBeforeCompressingString = 10;
+
+    CompressibleStringImpl::setPageBackground(visibilityState == PageVisibilityStateHidden);
     if (m_visibilityState == visibilityState)
         return;
     m_visibilityState = visibilityState;
@@ -372,6 +377,15 @@ void Page::setVisibilityState(PageVisibilityState visibilityState, bool isInitia
 
     if (!isInitialState && m_mainFrame && m_mainFrame->isLocalFrame())
         deprecatedLocalMainFrame()->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
@@ -584,6 +598,13 @@ 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)