Remove a UMA item WebCore.WebSocket.BinaryTypeChangesAfterOpen

We've collected enough data to make the decision. Remove it to save
binary size.

Bug: 584616
Change-Id: I8edda0afdde749a56f6b47fd377ab37dda420afb
Reviewed-on: https://chromium-review.googlesource.com/530867Reviewed-by: Ilya Sherman <isherman@chromium.org>
Reviewed-by: Adam Rice <ricea@chromium.org>
Commit-Queue: Takeshi Yoshino <tyoshino@chromium.org>
Cr-Commit-Position: refs/heads/master@{#478828}

third_party/WebKit/Source/modules/websockets/DOMWebSocket.cpp

@@ -227,7 +227,6 @@ DOMWebSocket::DOMWebSocket(ExecutionContext* context)
       consumed_buffered_amount_(0),
       buffered_amount_after_close_(0),
       binary_type_(kBinaryTypeBlob),
-      binary_type_changes_after_open_(0),
       subprotocol_(""),
       extensions_(""),
       event_queue_(EventQueue::Create(this)),
@@ -420,16 +419,6 @@ void DOMWebSocket::ReleaseChannel() {
   channel_ = nullptr;
 }
 
-void DOMWebSocket::LogBinaryTypeChangesAfterOpen() {
-  DEFINE_THREAD_SAFE_STATIC_LOCAL(
-      CustomCountHistogram, binary_type_changes_histogram,
-      ("WebCore.WebSocket.BinaryTypeChangesAfterOpen", 1, 1024, 10));
-  DVLOG(3) << "WebSocket " << static_cast<void*>(this)
-           << " logBinaryTypeChangesAfterOpen() logging "
-           << binary_type_changes_after_open_;
-  binary_type_changes_histogram.Count(binary_type_changes_after_open_);
-}
-
 void DOMWebSocket::send(const String& message,
                         ExceptionState& exception_state) {
   CString encoded_message = message.Utf8();
@@ -631,24 +620,16 @@ String DOMWebSocket::binaryType() const {
 
 void DOMWebSocket::setBinaryType(const String& binary_type) {
   if (binary_type == "blob") {
-    SetBinaryTypeInternal(kBinaryTypeBlob);
+    binary_type_ = kBinaryTypeBlob;
     return;
   }
   if (binary_type == "arraybuffer") {
-    SetBinaryTypeInternal(kBinaryTypeArrayBuffer);
+    binary_type_ = kBinaryTypeArrayBuffer;
     return;
   }
   NOTREACHED();
 }
 
-void DOMWebSocket::SetBinaryTypeInternal(BinaryType binary_type) {
-  if (binary_type_ == binary_type)
-    return;
-  binary_type_ = binary_type;
-  if (state_ == kOpen || state_ == kClosing)
-    ++binary_type_changes_after_open_;
-}
-
 const AtomicString& DOMWebSocket::InterfaceName() const {
   return EventTargetNames::DOMWebSocket;
 }
@@ -664,10 +645,8 @@ void DOMWebSocket::ContextDestroyed(ExecutionContext*) {
     channel_->Close(WebSocketChannel::kCloseEventCodeGoingAway, String());
     ReleaseChannel();
   }
-  if (state_ != kClosed) {
+  if (state_ != kClosed)
     state_ = kClosed;
-    LogBinaryTypeChangesAfterOpen();
-  }
 }
 
 bool DOMWebSocket::HasPendingActivity() const {
@@ -739,7 +718,6 @@ void DOMWebSocket::DidReceiveBinaryMessage(
 void DOMWebSocket::DidError() {
   NETWORK_DVLOG(1) << "WebSocket " << this << " didError()";
   state_ = kClosed;
-  LogBinaryTypeChangesAfterOpen();
   event_queue_->Dispatch(Event::Create(EventTypeNames::error));
 }
 

third_party/WebKit/Source/modules/websockets/DOMWebSocket.h

@@ -235,9 +235,6 @@ class MODULES_EXPORT DOMWebSocket : public EventTargetWithInlineData,
   void RecordReceiveTypeHistogram(WebSocketReceiveType);
   void RecordReceiveMessageSizeHistogram(WebSocketReceiveType, size_t);
 
-  void SetBinaryTypeInternal(BinaryType);
-  void LogBinaryTypeChangesAfterOpen();
-
   Member<WebSocketChannel> channel_;
 
   State state_;
@@ -248,7 +245,6 @@ class MODULES_EXPORT DOMWebSocket : public EventTargetWithInlineData,
   uint64_t consumed_buffered_amount_;
   uint64_t buffered_amount_after_close_;
   BinaryType binary_type_;
-  int binary_type_changes_after_open_;
   // The subprotocol the server selected.
   String subprotocol_;
   String extensions_;

tools/metrics/histograms/histograms.xml

@@ -82956,6 +82956,10 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="WebCore.WebSocket.BinaryTypeChangesAfterOpen">
+  <obsolete>
+    Deprecate 2017-06, as we've collected enough data to discuss. (see issue
+    584616).
+  </obsolete>
   <owner>yhirano@chromium.org</owner>
   <owner>ricea@chromium.org</owner>
   <owner>tyoshino@chromium.org</owner>