Revert r160071 "Web Animations: Implement AnimationClock and fix start time of animations"

Source/core/dom/Document.cpp

Index: Source/core/dom/Document.cpp
diff --git a/Source/core/dom/Document.cpp b/Source/core/dom/Document.cpp
index 061ea0cb8a16dc23a0512bb37d836d1296c01f96..94809f0a4995bf525a5a3826a0bfc0d086b849af 100644
--- a/Source/core/dom/Document.cpp
+++ b/Source/core/dom/Document.cpp
@@ -42,7 +42,6 @@
 #include "bindings/v8/ExceptionStatePlaceholder.h"
 #include "bindings/v8/ScriptController.h"
 #include "core/accessibility/AXObjectCache.h"
-#include "core/animation/AnimationClock.h"
 #include "core/animation/DocumentTimeline.h"
 #include "core/css/CSSDefaultStyleSheets.h"
 #include "core/css/CSSFontSelector.h"
@@ -460,7 +459,6 @@ Document::Document(const DocumentInit& initializer, DocumentClassFlags documentC
 #ifndef NDEBUG
     , m_didDispatchViewportPropertiesChanged(false)
 #endif
-    , m_animationClock(AnimationClock::create())
     , m_timeline(DocumentTimeline::create(this))
     , m_templateDocumentHost(0)
     , m_fonts(0)
@@ -1764,7 +1762,6 @@ void Document::updateStyleIfNeeded()
 
     AnimationUpdateBlock animationUpdateBlock(m_frame ? m_frame->animation() : 0);
     recalcStyle(NoChange);
-    m_animationClock->unfreeze();
 }
 
 void Document::updateStyleForNodeIfNeeded(Node* node)