Add HTML parser UMA for rewinds and chunk queue statistics.

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

 /*
  * Copyright (C) 2010 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 138 matching lines @@
     visitor->trace(m_parserScheduler);
     visitor->trace(m_xssAuditorDelegate);
     visitor->trace(m_scriptRunner);
     visitor->trace(m_preloader);
     ScriptableDocumentParser::trace(visitor);
     HTMLScriptRunnerHost::trace(visitor);
 }
 
 void HTMLDocumentParser::detach()
 {
+    if (!isParsingFragment() && m_parsedChunkQueue.get() && m_parsedChunkQueue->peakPendingChunkCount()) {
+        DEFINE_STATIC_LOCAL(CustomCountHistogram, peakPendingChunkHistogram, ("Parser.PeakPendingChunkCount", 1, 1000, 50));
+        peakPendingChunkHistogram.count(m_parsedChunkQueue->peakPendingChunkCount());
+        DEFINE_STATIC_LOCAL(CustomCountHistogram, peakPendingTokenHistogram, ("Parser.PeakPendingTokenCount", 1, 100000, 50));
+        peakPendingTokenHistogram.count(m_parsedChunkQueue->peakPendingTokenCount());
+    }
+
     if (m_haveBackgroundParser)
         stopBackgroundParser();
     DocumentParser::detach();
     if (m_scriptRunner)
         m_scriptRunner->detach();
     m_treeBuilder->detach();
     // FIXME: It seems wrong that we would have a preload scanner here.
     // Yet during fast/dom/HTMLScriptElement/script-load-events.html we do.
     m_preloadScanner.reset();
     m_insertionPreloadScanner.reset();
@@ skipping 206 matching lines @@
         && chunk->treeBuilderState == HTMLTreeBuilderSimulator::stateFor(m_treeBuilder.get())) {
         ASSERT(token->isUninitialized());
         return;
     }
 
     discardSpeculationsAndResumeFrom(std::move(chunk), std::move(token), std::move(tokenizer));
 }
 
 void HTMLDocumentParser::discardSpeculationsAndResumeFrom(PassOwnPtr<ParsedChunk> lastChunkBeforeScript, PassOwnPtr<HTMLToken> token, PassOwnPtr<HTMLTokenizer> tokenizer)
 {
+    TRACE_EVENT0("blink,loading", "HTMLDocumentParser::discardSpeculationsAndResumeFrom");

[kouhei (in TOK), 2016/06/17 11:20:57]

caseq: Would you review this TRACE_EVENT?

     m_weakFactory.revokeAll();
+
+    size_t discardedTokenCount = 0;
+    for (const auto& speculation : m_speculations) {
+        discardedTokenCount += speculation->tokens->size();
+    }
+    DEFINE_STATIC_LOCAL(CustomCountHistogram, discardedTokenCountHistogram, ("Parser.DiscardedTokenCount", 1, 100000, 50));
+    discardedTokenCountHistogram.count(discardedTokenCount);
+
     m_speculations.clear();
 
     OwnPtr<BackgroundHTMLParser::Checkpoint> checkpoint = adoptPtr(new BackgroundHTMLParser::Checkpoint);
     checkpoint->parser = m_weakFactory.createWeakPtr();
     checkpoint->token = std::move(token);
     checkpoint->tokenizer = std::move(tokenizer);
     checkpoint->treeBuilderState = HTMLTreeBuilderSimulator::stateFor(m_treeBuilder.get());
     checkpoint->inputCheckpoint = lastChunkBeforeScript->inputCheckpoint;
     checkpoint->preloadScannerCheckpoint = lastChunkBeforeScript->preloadScannerCheckpoint;
     checkpoint->unparsedInput = m_input.current().toString().isolatedCopy();
@@ skipping 713 matching lines @@
         DEFINE_STATIC_LOCAL(CustomCountHistogram, successHistogram, ("PreloadScanner.DocumentWrite.ExecutionTime.Success", 1, 10000, 50));
         successHistogram.count(duration);
     } else {
         DEFINE_STATIC_LOCAL(CustomCountHistogram, failureHistogram, ("PreloadScanner.DocumentWrite.ExecutionTime.Failure", 1, 10000, 50));
         failureHistogram.count(duration);
     }
 
 }
 
 } // namespace blink