Add HTML parser UMA for rewinds and chunk queue statistics.

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

Index: third_party/WebKit/Source/core/html/parser/ParsedChunkQueue.cpp
diff --git a/third_party/WebKit/Source/core/html/parser/ParsedChunkQueue.cpp b/third_party/WebKit/Source/core/html/parser/ParsedChunkQueue.cpp
index 263c9a9719085e123cb4b284932ce9686b1625fa..82ecd2c2721030b327c3129a0b25650134153666 100644
--- a/third_party/WebKit/Source/core/html/parser/ParsedChunkQueue.cpp
+++ b/third_party/WebKit/Source/core/html/parser/ParsedChunkQueue.cpp
@@ -4,6 +4,8 @@
 
 #include "core/html/parser/ParsedChunkQueue.h"
 
+#include <algorithm>
+
 namespace blink {
 
 ParsedChunkQueue::ParsedChunkQueue()
@@ -18,8 +20,13 @@ bool ParsedChunkQueue::enqueue(PassOwnPtr<HTMLDocumentParser::ParsedChunk> chunk
 {
     MutexLocker locker(m_mutex);
 
+    m_pendingTokenCount += chunk->tokens->size();
+    m_peakPendingTokenCount = std::max(m_peakPendingTokenCount, m_pendingTokenCount);
+
     bool wasEmpty = m_pendingChunks.isEmpty();
     m_pendingChunks.append(std::move(chunk));
+    m_peakPendingChunkCount = std::max(m_peakPendingChunkCount, m_pendingChunks.size());
+
     return wasEmpty;
 }
 
@@ -27,6 +34,7 @@ void ParsedChunkQueue::clear()
 {
     MutexLocker locker(m_mutex);
 
+    m_pendingTokenCount = 0;
     m_pendingChunks.clear();
 }
 
@@ -38,4 +46,16 @@ void ParsedChunkQueue::takeAll(Vector<OwnPtr<HTMLDocumentParser::ParsedChunk>>&
     m_pendingChunks.swap(vector);
 }
 
+size_t ParsedChunkQueue::peakPendingChunkCount()
+{
+    MutexLocker locker(m_mutex);
+    return m_peakPendingChunkCount;
+}
+
+size_t ParsedChunkQueue::peakPendingTokenCount()
+{
+    MutexLocker locker(m_mutex);
+    return m_peakPendingTokenCount;
+}
+
 } // namespace blink