Revert "Measure whether muted videos that started playing with play() become visible at some point"

third_party/WebKit/Source/core/html/AutoplayUmaHelper.h

Index: third_party/WebKit/Source/core/html/AutoplayUmaHelper.h
diff --git a/third_party/WebKit/Source/core/html/AutoplayUmaHelper.h b/third_party/WebKit/Source/core/html/AutoplayUmaHelper.h
deleted file mode 100644
index 913b74ed90c7fa3f4c6ec59ae33387d00890f5c8..0000000000000000000000000000000000000000
--- a/third_party/WebKit/Source/core/html/AutoplayUmaHelper.h
+++ /dev/null
@@ -1,67 +0,0 @@
-// Copyright 2016 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef AutoplayUmaHelper_h
-#define AutoplayUmaHelper_h
-
-#include "core/events/EventListener.h"
-#include "platform/heap/Handle.h"
-
-namespace blink {
-
-// These values are used for histograms. Do not reorder.
-enum class AutoplaySource {
-    // Autoplay comes from HTMLMediaElement `autoplay` attribute.
-    Attribute = 0,
-    // Autoplay comes from `play()` method.
-    Method = 1,
-    // This enum value must be last.
-    NumberOfSources = 2,
-};
-
-// These values are used for histograms. Do not reorder.
-enum class AutoplayUnmuteActionStatus {
-    Failure = 0,
-    Success = 1,
-    NumberOfStatus = 2,
-};
-
-class ElementVisibilityObserver;
-class HTMLMediaElement;
-
-class AutoplayUmaHelper final : public EventListener {
-public:
-    static AutoplayUmaHelper* create(HTMLMediaElement*);
-
-    ~AutoplayUmaHelper();
-
-    bool operator==(const EventListener&) const override;
-
-    void onAutoplayInitiated(AutoplaySource);
-    void onElementDestroyed();
-
-    void recordAutoplayUnmuteStatus(AutoplayUnmuteActionStatus);
-
-    void onVisibilityChangedForVideoMutedPlayMethod(bool isVisible);
-
-    DECLARE_VIRTUAL_TRACE();
-
-private:
-    explicit AutoplayUmaHelper(HTMLMediaElement*);
-
-    void handleEvent(ExecutionContext*, Event*) override;
-
-    void handlePlayingEvent();
-
-    // The autoplay source. Use AutoplaySource::NumberOfSources for invalid source.
-    AutoplaySource m_source;
-    // The media element this UMA helper is attached to. |m_element| owns |this|.
-    WeakMember<HTMLMediaElement> m_element;
-    // The observer is used to observe whether a muted video autoplaying by play() method become visible at some point.
-    Member<ElementVisibilityObserver> m_videoMutedPlayMethodVisibilityObserver;
-};
-
-} // namespace blink
-
-#endif // AutoplayUmaHelper_h