Throttle rendering pipeline for invisible frames

third_party/WebKit/Source/core/dom/DocumentLifecycle.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 116 matching lines @@
 
         ~DetachScope()
         {
             m_documentLifecycle.decrementDetachCount();
         }
 
     private:
         DocumentLifecycle& m_documentLifecycle;
     };
 
+    class PreventThrottlingScope {
+        STACK_ALLOCATED();
+        WTF_MAKE_NONCOPYABLE(PreventThrottlingScope);
+    public:
+        PreventThrottlingScope(DocumentLifecycle&);
+        ~PreventThrottlingScope();
+
+    private:
+        DocumentLifecycle& m_lifecycle;
+    };
+
     DocumentLifecycle();
     ~DocumentLifecycle();
 
     bool isActive() const { return m_state > Inactive && m_state < Stopping; }
     State state() const { return m_state; }
 
     bool stateAllowsTreeMutations() const;
     bool stateAllowsLayoutTreeMutations() const;
     bool stateAllowsDetach() const;
     bool stateAllowsLayoutInvalidation() const;
     bool stateAllowsLayoutTreeNotifications() const;
 
     void advanceTo(State);
     void ensureStateAtMost(State);
 
     bool inDetach() const { return m_detachCount; }
     void incrementDetachCount() { m_detachCount++; }
     void decrementDetachCount()
     {
         ASSERT(m_detachCount > 0);
         m_detachCount--;
     }
 
+    bool throttlingAllowed() const;
+
 #if ENABLE(ASSERT)
     static const char* stateAsDebugString(const State);
 #endif
 
 private:
 #if ENABLE(ASSERT)
     bool canAdvanceTo(State) const;
     bool canRewindTo(State) const;
 #endif
 
+    void incrementPreventThrottlingCount();
+    void decrementPreventThrottlingCount();
+
     State m_state;
     int m_detachCount;
 };
 
 inline bool DocumentLifecycle::stateAllowsTreeMutations() const
 {
     // FIXME: We should not allow mutations in InPreLayout or AfterPerformLayout either,
     // but we need to fix MediaList listeners and plugins first.
     return m_state != InStyleRecalc
         && m_state != InPerformLayout
@@ skipping 35 matching lines @@
         && m_state != InCompositingUpdate
         && m_state != InPaintInvalidation
         && m_state != InUpdatePaintProperties
         && m_state != InPaint
         && m_state != InCompositingForSlimmingPaintV2;
 }
 
 } // namespace blink
 
 #endif