Introduce ContentChangeObserver class

https://bugs.webkit.org/show_bug.cgi?id=194977
<rdar://problem/48338115>

Reviewed by Simon Fraser.

Source/WebCore:

This patch is about piping through all the related WK* calls.

* SourcesCocoa.txt:
* WebCore.xcodeproj/project.pbxproj:
* dom/Document.cpp:
(WebCore::Document::scheduleStyleRecalc):
(WebCore::Document::updateStyleIfNeeded):
(WebCore::Document::platformSuspendOrStopActiveDOMObjects):
* loader/FrameLoader.cpp:
* page/DOMTimer.cpp:
(WebCore::DOMTimer::install):
(WebCore::DOMTimer::fired):
* page/DOMWindow.cpp:
(WebCore::DOMWindow::clearTimeout):
* page/Frame.cpp:
(WebCore::Frame::willDetachPage):
* page/Page.h:
(WebCore::Page::contentChangeObserver):
* page/ios/EventHandlerIOS.mm:
(WebCore::EventHandler::mouseMoved):
* rendering/updating/RenderTreeUpdater.cpp:
(WebCore::RenderTreeUpdater::updateElementRenderer):
(WebCore::CheckForVisibilityChange::CheckForVisibilityChange):
(WebCore::CheckForVisibilityChange::~CheckForVisibilityChange):

Source/WebKit:

* WebProcess/WebPage/ios/WebPageIOS.mm:
(WebKit::WebPage::handleSyntheticClick):
(WebKit::WebPage::completePendingSyntheticClickForContentChangeObserver):

Source/WebKitLegacy/ios:

* WebCoreSupport/WebChromeClientIOS.mm:
(WebChromeClientIOS::observedContentChange):
(WebChromeClientIOS::clearContentChangeObservers):


Canonical link: https://commits.webkit.org/209356@main
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@242032 268f45cc-cd09-0410-ab3c-d52691b4dbfc

Source/WebCore/ChangeLog

@@ -1,3 +1,36 @@
+2019-02-24  Zalan Bujtas  <zalan@apple.com>
+
+        Introduce ContentChangeObserver class
+        https://bugs.webkit.org/show_bug.cgi?id=194977
+        <rdar://problem/48338115>
+
+        Reviewed by Simon Fraser.
+
+        This patch is about piping through all the related WK* calls. 
+
+        * SourcesCocoa.txt:
+        * WebCore.xcodeproj/project.pbxproj:
+        * dom/Document.cpp:
+        (WebCore::Document::scheduleStyleRecalc):
+        (WebCore::Document::updateStyleIfNeeded):
+        (WebCore::Document::platformSuspendOrStopActiveDOMObjects):
+        * loader/FrameLoader.cpp:
+        * page/DOMTimer.cpp:
+        (WebCore::DOMTimer::install):
+        (WebCore::DOMTimer::fired):
+        * page/DOMWindow.cpp:
+        (WebCore::DOMWindow::clearTimeout):
+        * page/Frame.cpp:
+        (WebCore::Frame::willDetachPage):
+        * page/Page.h:
+        (WebCore::Page::contentChangeObserver):
+        * page/ios/EventHandlerIOS.mm:
+        (WebCore::EventHandler::mouseMoved):
+        * rendering/updating/RenderTreeUpdater.cpp:
+        (WebCore::RenderTreeUpdater::updateElementRenderer):
+        (WebCore::CheckForVisibilityChange::CheckForVisibilityChange):
+        (WebCore::CheckForVisibilityChange::~CheckForVisibilityChange):
+
 2019-02-24  Simon Fraser  <simon.fraser@apple.com>
 
         Migrate from "fixedPositionRect" to "layoutViewport" in the scrolling tree

Source/WebCore/SourcesCocoa.txt

@@ -131,6 +131,7 @@ page/cocoa/ResourceUsageOverlayCocoa.mm
 page/cocoa/ResourceUsageThreadCocoa.mm
 page/cocoa/SettingsBaseCocoa.mm
 
+page/ios/ContentChangeObserver.mm
 page/ios/EventHandlerIOS.mm
 page/ios/FrameIOS.mm
 page/ios/WebEventRegion.mm

Source/WebCore/WebCore.xcodeproj/project.pbxproj

@@ -2065,6 +2065,7 @@
 		6F995A3A1A70833700A735F4 /* JSWebGLVertexArrayObject.h in Headers */ = {isa = PBXBuildFile; fileRef = 6F995A301A70833700A735F4 /* JSWebGLVertexArrayObject.h */; };
 		6FA4454E898F2FC168BC38C1 /* JSBeforeUnloadEvent.h in Headers */ = {isa = PBXBuildFile; fileRef = 29E04A27BED2F81F98E9022B /* JSBeforeUnloadEvent.h */; };
 		6FB11B5C21783FD000E2A574 /* TextUtil.h in Headers */ = {isa = PBXBuildFile; fileRef = 6FB11B5921783FCF00E2A574 /* TextUtil.h */; settings = {ATTRIBUTES = (Private, ); }; };
+		6FB5E214221F2453003989CF /* ContentChangeObserver.h in Headers */ = {isa = PBXBuildFile; fileRef = 6FB5E212221F2447003989CF /* ContentChangeObserver.h */; settings = {ATTRIBUTES = (Private, ); }; };
 		6FE198172178397C00446F08 /* InlineLineBreaker.h in Headers */ = {isa = PBXBuildFile; fileRef = 6FE198152178397C00446F08 /* InlineLineBreaker.h */; settings = {ATTRIBUTES = (Private, ); }; };
 		6FE7CFA22177EEF2005B1573 /* InlineItem.h in Headers */ = {isa = PBXBuildFile; fileRef = 6FE7CFA02177EEF1005B1573 /* InlineItem.h */; };
 		6FE7CFA42177EF10005B1573 /* LayoutLineBreakBox.h in Headers */ = {isa = PBXBuildFile; fileRef = 6FE7CFA32177EF10005B1573 /* LayoutLineBreakBox.h */; settings = {ATTRIBUTES = (Private, ); }; };
@@ -9234,13 +9235,15 @@
 		6F995A301A70833700A735F4 /* JSWebGLVertexArrayObject.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = JSWebGLVertexArrayObject.h; sourceTree = "<group>"; };
 		6FB11B5921783FCF00E2A574 /* TextUtil.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = TextUtil.h; sourceTree = "<group>"; };
 		6FB11B5B21783FCF00E2A574 /* TextUtil.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = TextUtil.cpp; sourceTree = "<group>"; };
+		6FB5E212221F2447003989CF /* ContentChangeObserver.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = ContentChangeObserver.h; sourceTree = "<group>"; };
 		6FBB860520B464B600DAD938 /* FormattingContextGeometry.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; path = FormattingContextGeometry.cpp; sourceTree = "<group>"; };
 		6FE198132178397B00446F08 /* InlineLineBreaker.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = InlineLineBreaker.cpp; sourceTree = "<group>"; };
 		6FE198152178397C00446F08 /* InlineLineBreaker.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = InlineLineBreaker.h; sourceTree = "<group>"; };
 		6FE7AA2621C37B6300296DCD /* MarginTypes.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = MarginTypes.h; sourceTree = "<group>"; };
 		6FE7CFA02177EEF1005B1573 /* InlineItem.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = InlineItem.h; sourceTree = "<group>"; };
 		6FE7CFA32177EF10005B1573 /* LayoutLineBreakBox.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = LayoutLineBreakBox.h; sourceTree = "<group>"; };
 		6FE7CFA52177F069005B1573 /* LayoutLineBreakBox.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = LayoutLineBreakBox.cpp; sourceTree = "<group>"; };
+		6FE9F09222211035004C5082 /* ContentChangeObserver.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = ContentChangeObserver.mm; sourceTree = "<group>"; };
 		6FFDC43E212EFF1600A9CA91 /* FloatAvoider.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = FloatAvoider.cpp; sourceTree = "<group>"; };
 		6FFDC440212EFF1600A9CA91 /* FloatAvoider.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = FloatAvoider.h; sourceTree = "<group>"; };
 		709A01FD1E3D0BCC006B0D4C /* ModuleFetchFailureKind.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ModuleFetchFailureKind.h; sourceTree = "<group>"; };
@@ -16585,6 +16588,8 @@
 		18A6CD6F0D8F2025001DC3CE /* ios */ = {
 			isa = PBXGroup;
 			children = (
+				6FB5E212221F2447003989CF /* ContentChangeObserver.h */,
+				6FE9F09222211035004C5082 /* ContentChangeObserver.mm */,
 				FE6938B51045D67E008EABB6 /* EventHandlerIOS.mm */,
 				FED13D3B0CEA936A00D89466 /* FrameIOS.mm */,
 				225A16B30D5C11E900090295 /* WebEventRegion.h */,
@@ -28687,6 +28692,7 @@
 				2DAF343D1EA7E0F100382CD3 /* ConstantPropertyMap.h in Headers */,
 				A818721C0977D3C0005826D9 /* ContainerNode.h in Headers */,
 				E1A1470811102B1500EEC0F3 /* ContainerNodeAlgorithms.h in Headers */,
+				6FB5E214221F2453003989CF /* ContentChangeObserver.h in Headers */,
 				BC5EB9810E82072500B25965 /* ContentData.h in Headers */,
 				51B45D211AB8D1E200117CD2 /* ContentExtension.h in Headers */,
 				5CDFA6C81AA4F2DA00EA8746 /* ContentExtensionActions.h in Headers */,

Source/WebCore/dom/Document.cpp

@@ -258,6 +258,7 @@
 #endif
 
 #if PLATFORM(IOS_FAMILY)
+#include "ContentChangeObserver.h"
 #include "CSSFontSelector.h"
 #include "DeviceMotionClientIOS.h"
 #include "DeviceMotionController.h"
@@ -266,8 +267,6 @@
 #include "Geolocation.h"
 #include "Navigator.h"
 #include "NavigatorGeolocation.h"
-#include "WKContentObservation.h"
-#include "WKContentObservationInternal.h"
 #endif
 
 #if ENABLE(IOS_GESTURE_EVENTS)
@@ -1812,9 +1811,12 @@ void Document::scheduleStyleRecalc()
     ASSERT(childNeedsStyleRecalc() || m_needsFullStyleRebuild);
 
 #if PLATFORM(IOS_FAMILY)
-    if (WKIsObservingStyleRecalcScheduling()) {
-        LOG_WITH_STREAM(ContentObservation, stream << "Document(" << this << ")::scheduleStyleRecalc: register this style recalc schedule and observe when it fires.");
-        WKSetObservedContentChange(WKContentIndeterminateChange);
+    if (auto* page = this->page()) {
+        auto& contentChangeObserver = page->contentChangeObserver();
+        if (contentChangeObserver.isObservingStyleRecalcScheduling()) {
+            LOG_WITH_STREAM(ContentObservation, stream << "Document(" << this << ")::scheduleStyleRecalc: register this style recalc schedule and observe when it fires.");
+            contentChangeObserver.setObservedContentChange(WKContentIndeterminateChange);
+        }
     }
 #endif
 
@@ -2048,11 +2050,15 @@ bool Document::updateStyleIfNeeded()
     }
 
 #if PLATFORM(IOS_FAMILY)
-    auto observingContentChange = WKShouldObserveNextStyleRecalc();
-    if (observingContentChange) {
-        LOG_WITH_STREAM(ContentObservation, stream << "Document(" << this << ")::scheduleStyleRecalc: start observing content change.");
-        WKSetShouldObserveNextStyleRecalc(false);
-        WKStartObservingContentChanges();
+    auto observingContentChange = false;
+    if (auto* page = this->page()) {
+        auto& contentChangeObserver = page->contentChangeObserver();
+        observingContentChange = contentChangeObserver.shouldObserveNextStyleRecalc();
+        if (observingContentChange) {
+            LOG_WITH_STREAM(ContentObservation, stream << "Document(" << this << ")::scheduleStyleRecalc: start observing content change.");
+            contentChangeObserver.setShouldObserveNextStyleRecalc(false);
+            contentChangeObserver.startObservingContentChanges();
+        }
     }
 #endif
     // The early exit above for !needsStyleRecalc() is needed when updateWidgetPositions() is called in runOrScheduleAsynchronousTasks().
@@ -2061,15 +2067,15 @@ bool Document::updateStyleIfNeeded()
     resolveStyle();
 
 #if PLATFORM(IOS_FAMILY)
-    if (observingContentChange) {
+    if (observingContentChange && page()) {
         LOG_WITH_STREAM(ContentObservation, stream << "Document(" << this << ")::scheduleStyleRecalc: stop observing content change.");
-        WKStopObservingContentChanges();
+        auto& contentChangeObserver = page()->contentChangeObserver();
+        contentChangeObserver.stopObservingContentChanges();
 
-        auto inDeterminedState = WKObservedContentChange() == WKContentVisibilityChange || !WebThreadCountOfObservedDOMTimers();  
+        auto inDeterminedState = contentChangeObserver.observedContentChange() == WKContentVisibilityChange || !contentChangeObserver.countOfObservedDOMTimers();  
         if (inDeterminedState) {
             LOG_WITH_STREAM(ContentObservation, stream << "Document(" << this << ")::scheduleStyleRecalc: notify the pending synthetic click handler.");
-            if (auto* page = this->page())
-                page->chrome().client().observedContentChange(*frame());
+            page()->chrome().client().observedContentChange(*frame());
         } else {
             LOG_WITH_STREAM(ContentObservation, stream << "Document(" << this << ")::scheduleStyleRecalc: can't decided it yet.");
         }
@@ -2651,13 +2657,13 @@ bool Document::shouldBypassMainWorldContentSecurityPolicy() const
 void Document::platformSuspendOrStopActiveDOMObjects()
 {
 #if PLATFORM(IOS_FAMILY)
-    if (WebThreadCountOfObservedDOMTimers() > 0) {
-        LOG_WITH_STREAM(ContentObservation, stream << "Document::platformSuspendOrStopActiveDOMObjects: remove registered timers.");
-        if (auto* frame = this->frame()) {
-            if (auto* page = frame->page())
-                page->chrome().client().clearContentChangeObservers(*frame);
-        }
-    }
+    if (!page() || !frame())
+        return;
+    auto& page = *this->page();
+    if (!page.contentChangeObserver().countOfObservedDOMTimers())
+        return;
+    LOG_WITH_STREAM(ContentObservation, stream << "Document::platformSuspendOrStopActiveDOMObjects: remove registered timers.");
+    page.chrome().client().clearContentChangeObservers(*frame());
 #endif
 }
 

Source/WebCore/loader/FrameLoader.cpp

@@ -145,7 +145,6 @@
 #include "DocumentType.h"
 #include "ResourceLoader.h"
 #include "RuntimeApplicationChecks.h"
-#include "WKContentObservation.h"
 #endif
 
 #define RELEASE_LOG_IF_ALLOWED(fmt, ...) RELEASE_LOG_IF(isAlwaysOnLoggingAllowed(), Network, "%p - FrameLoader::" fmt, this, ##__VA_ARGS__)

Source/WebCore/page/DOMTimer.cpp

@@ -44,9 +44,8 @@
 #if PLATFORM(IOS_FAMILY)
 #include "Chrome.h"
 #include "ChromeClient.h"
+#include "ContentChangeObserver.h"
 #include "Frame.h"
-#include "WKContentObservation.h"
-#include "WKContentObservationInternal.h"
 #endif
 
 namespace WebCore {
@@ -219,24 +218,32 @@ int DOMTimer::install(ScriptExecutionContext& context, std::unique_ptr<Scheduled
     // This reference will be released automatically when a one-shot timer fires, when the context
     // is destroyed, or if explicitly cancelled by removeById. 
     DOMTimer* timer = new DOMTimer(context, WTFMove(action), timeout, singleShot);
-#if PLATFORM(IOS_FAMILY)
-    if (WKIsObservingDOMTimerScheduling() && is<Document>(context)) {
-        bool didDeferTimeout = context.activeDOMObjectsAreSuspended();
-        if (!didDeferTimeout && timeout <= 250_ms && singleShot) {
-            WKSetObservedContentChange(WKContentIndeterminateChange);
-            WebThreadAddObservedDOMTimer(timer);
-            LOG_WITH_STREAM(ContentObservation, stream << "DOMTimer::install: registed this timer: (" << timer << ") and observe when it fires.");
-        }
-    }
-#endif
-
     timer->suspendIfNeeded();
     InspectorInstrumentation::didInstallTimer(context, timer->m_timeoutId, timeout, singleShot);
 
     // Keep track of nested timer installs.
     if (NestedTimersMap* nestedTimers = NestedTimersMap::instanceForContext(context))
         nestedTimers->add(timer->m_timeoutId, *timer);
 
+#if PLATFORM(IOS_FAMILY)
+    auto startObservingThisTimerIfNeeded = [&] {
+        if (!is<Document>(context))
+            return;
+        if (context.activeDOMObjectsAreSuspended())
+            return;
+        if (timeout > 250_ms || !singleShot)
+            return;
+        auto& contentChangeObserver = downcast<Document>(context).page()->contentChangeObserver();
+        if (!contentChangeObserver.isObservingDOMTimerScheduling())
+            return;
+
+        contentChangeObserver.setObservedContentChange(WKContentIndeterminateChange);
+        contentChangeObserver.addObservedDOMTimer(*timer);
+        LOG_WITH_STREAM(ContentObservation, stream << "DOMTimer::install: register this timer: (" << m_timeoutId << ") and observe when it fires.");
+    };
+
+    startObservingThisTimerIfNeeded();
+#endif
     return timer->m_timeoutId;
 }
 
@@ -342,18 +349,23 @@ void DOMTimer::fired()
     context.removeTimeout(m_timeoutId);
 
 #if PLATFORM(IOS_FAMILY)
-    auto isObversingLastTimer = false;
+    auto isObservingLastTimer = false;
     auto shouldBeginObservingChanges = false;
-    if (is<Document>(context)) {
-        isObversingLastTimer = WebThreadCountOfObservedDOMTimers() == 1;
-        shouldBeginObservingChanges = WebThreadContainsObservedDOMTimer(this);
+    Page* page = nullptr;
+    if (is<Document>(context) && downcast<Document>(context).page()) {
+        page = downcast<Document>(context).page();
+        auto& contentChangeObserver = page->contentChangeObserver();
+        isObservingLastTimer = contentChangeObserver.countOfObservedDOMTimers() == 1;
+        shouldBeginObservingChanges = contentChangeObserver.containsObservedDOMTimer(*this);
     }
 
     if (shouldBeginObservingChanges) {
-        LOG_WITH_STREAM(ContentObservation, stream << "DOMTimer::fired: start observing (" << this << ") timer callback.");
-        WKStartObservingContentChanges();
-        WKStartObservingStyleRecalcScheduling();
-        WebThreadRemoveObservedDOMTimer(this);
+        ASSERT(page);
+        LOG_WITH_STREAM(ContentObservation, stream << "DOMTimer::fired: start observing (" << m_timeoutId << ") timer callback.");
+        auto& contentChangeObserver = page->contentChangeObserver();
+        contentChangeObserver.startObservingContentChanges();
+        contentChangeObserver.startObservingStyleRecalcScheduling();
+        contentChangeObserver.removeObservedDOMTimer(*this);
     }
 #endif
 
@@ -366,22 +378,22 @@ void DOMTimer::fired()
 
 #if PLATFORM(IOS_FAMILY)
     if (shouldBeginObservingChanges) {
-        LOG_WITH_STREAM(ContentObservation, stream << "DOMTimer::fired: stop observing (" << this << ") timer callback.");
-        WKStopObservingStyleRecalcScheduling();
-        WKStopObservingContentChanges();
+        ASSERT(page);
+        LOG_WITH_STREAM(ContentObservation, stream << "DOMTimer::fired: stop observing (" << m_timeoutId << ") timer callback.");
+        auto& contentChangeObserver = page->contentChangeObserver();
+        contentChangeObserver.stopObservingStyleRecalcScheduling();
+        contentChangeObserver.stopObservingContentChanges();
 
-        auto observedContentChange = WKObservedContentChange();
+        auto observedContentChange = contentChangeObserver.observedContentChange();
         // Check if the timer callback triggered either a sync or async style update.
-        auto inDeterminedState = observedContentChange == WKContentVisibilityChange || (isObversingLastTimer && observedContentChange == WKContentNoChange);  
+        auto inDeterminedState = observedContentChange == WKContentVisibilityChange || (isObservingLastTimer && observedContentChange == WKContentNoChange);  
         if (inDeterminedState) {
-            LOG(ContentObservation, "DOMTimer::fired: in determined state.");
-            auto& document = downcast<Document>(context);
-            if (auto* page = document.page())
-                page->chrome().client().observedContentChange(*document.frame());
+            LOG_WITH_STREAM(ContentObservation, "DOMTimer::fired(" << m_timeoutId << "): in determined state.");
+            page->chrome().client().observedContentChange(*downcast<Document>(context).frame());
         } else if (observedContentChange == WKContentIndeterminateChange) {
             // An async style recalc has been scheduled. Let's observe it.
-            LOG(ContentObservation, "DOMTimer::fired: wait until next style recalc fires.");
-            WKSetShouldObserveNextStyleRecalc(true);
+            LOG_WITH_STREAM(ContentObservation, "DOMTimer::fired(" << m_timeoutId << "): wait until next style recalc fires.");
+            contentChangeObserver.setShouldObserveNextStyleRecalc(true);
         }
     }
 #endif

Source/WebCore/page/DOMWindow.cpp

@@ -139,11 +139,9 @@
 #endif
 
 #if PLATFORM(IOS_FAMILY)
-#include "WKContentObservation.h"
-#include "WKContentObservationInternal.h"
+#include "ContentChangeObserver.h"
 #endif
 
-
 namespace WebCore {
 using namespace Inspector;
 
@@ -1684,21 +1682,26 @@ ExceptionOr<int> DOMWindow::setTimeout(JSC::ExecState& state, std::unique_ptr<Sc
 void DOMWindow::clearTimeout(int timeoutId)
 {
 #if PLATFORM(IOS_FAMILY)
-    if (auto* frame = this->frame()) {
-        Document* document = frame->document();
-        if (timeoutId > 0 && document) {
-            DOMTimer* timer = document->findTimeout(timeoutId);
-            if (timer && WebThreadContainsObservedDOMTimer(timer)) {
-                LOG_WITH_STREAM(ContentObservation, stream << "DOMWindow::clearTimeout: remove registered timer (" << timer << ")");
-                WebThreadRemoveObservedDOMTimer(timer);
-
-                if (!WebThreadCountOfObservedDOMTimers()) {
-                    if (Page* page = frame->page())
-                        page->chrome().client().observedContentChange(*frame);
-                }
-            }
-        }
-    }
+    auto handleObservedTimerCancelIfNeeded = [&] {
+        if (!frame() || !frame()->document() || !frame()->document()->page())
+            return;
+        if (timeoutId <= 0)
+            return;
+        auto& document = *frame()->document();
+        auto* timer = document.findTimeout(timeoutId);
+        if (!timer)
+            return;
+        auto& page = *document.page();
+        auto& contentChangeObserver = page.contentChangeObserver();
+        if (!contentChangeObserver.containsObservedDOMTimer(*timer))
+            return;
+        LOG_WITH_STREAM(ContentObservation, stream << "DOMWindow::clearTimeout: remove registered timer (" << timer << ")");
+        contentChangeObserver.removeObservedDOMTimer(*timer);
+        if (contentChangeObserver.countOfObservedDOMTimers())
+            return;
+        page.chrome().client().observedContentChange(*frame());
+    };
+    handleObservedTimerCancelIfNeeded();
 #endif
     ScriptExecutionContext* context = scriptExecutionContext();
     if (!context)