Add HTML parser UMA for rewinds and chunk queue statistics.

third_party/WebKit/Source/core/html/parser/BackgroundHTMLParser.cpp

 /*
  * 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 11 matching lines @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "core/html/parser/BackgroundHTMLParser.h"
 
 #include "core/HTMLNames.h"
 #include "core/html/parser/HTMLDocumentParser.h"
 #include "core/html/parser/TextResourceDecoder.h"
 #include "core/html/parser/XSSAuditor.h"
+#include "platform/Histogram.h"
 #include "platform/ThreadSafeFunctional.h"
 #include "platform/TraceEvent.h"
 #include "public/platform/Platform.h"
 #include "public/platform/WebTaskRunner.h"
+#include "wtf/CurrentTime.h"
 #include "wtf/PtrUtil.h"
 #include "wtf/text/TextPosition.h"
 #include <memory>
 
 namespace blink {
 
 // On a network with high latency and high bandwidth, using a device
 // with a fast CPU, we could end up speculatively tokenizing
 // the whole document, well ahead of when the main-thread actually needs it.
 // This is a waste of memory (and potentially time if the speculation fails).
@@ skipping 236 matching lines @@
 {
     if (m_pendingTokens->isEmpty())
         return;
 
 #if ENABLE(ASSERT)
     checkThatTokensAreSafeToSendToAnotherThread(m_pendingTokens.get());
     checkThatPreloadsAreSafeToSendToAnotherThread(m_pendingPreloads);
     checkThatXSSInfosAreSafeToSendToAnotherThread(m_pendingXSSInfos);
 #endif
 
+    double chunkStartTime = monotonicallyIncreasingTimeMS();
     std::unique_ptr<HTMLDocumentParser::ParsedChunk> chunk = wrapUnique(new HTMLDocumentParser::ParsedChunk);
     TRACE_EVENT_WITH_FLOW0("blink,loading", "BackgroundHTMLParser::sendTokensToMainThread", chunk.get(), TRACE_EVENT_FLAG_FLOW_OUT);
+
     chunk->preloads.swap(m_pendingPreloads);
     if (m_viewportDescription.set)
         chunk->viewport = m_viewportDescription;
     chunk->xssInfos.swap(m_pendingXSSInfos);
     chunk->tokenizerState = m_tokenizer->getState();
     chunk->treeBuilderState = m_treeBuilderSimulator.state();
     chunk->inputCheckpoint = m_input.createCheckpoint(m_pendingTokens->size());
     chunk->preloadScannerCheckpoint = m_preloadScanner->createCheckpoint();
     chunk->tokens = std::move(m_pendingTokens);
     chunk->startingScript = m_startingScript;
     chunk->likelyDocumentWriteScriptIndices.swap(m_likelyDocumentWriteScriptIndices);
     m_startingScript = false;
 
     bool isEmpty = m_parsedChunkQueue->enqueue(std::move(chunk));
+
+    DEFINE_STATIC_LOCAL(CustomCountHistogram, chunkEnqueueTime, ("Parser.ChunkEnqueueTime", 1, 10000, 50));
+    chunkEnqueueTime.count(monotonicallyIncreasingTimeMS() - chunkStartTime);
+
     if (isEmpty) {
         m_loadingTaskRunner->postTask(
             BLINK_FROM_HERE,
             threadSafeBind(&HTMLDocumentParser::notifyPendingParsedChunks, m_parser));
     }
 
     m_pendingTokens = wrapUnique(new CompactHTMLTokenStream);
 }
 
 } // namespace blink