...

chrome/common/metrics_helpers.cc

Index: chrome/common/metrics_helpers.cc
===================================================================
--- chrome/common/metrics_helpers.cc	(revision 49384)
+++ chrome/common/metrics_helpers.cc	(working copy)
@@ -15,6 +15,7 @@
 #include "base/basictypes.h"
 #include "base/file_util.h"
 #include "base/md5.h"
+#include "base/perftimer.h"
 #include "base/scoped_ptr.h"
 #include "base/string_util.h"
 #include "base/sys_info.h"
@@ -47,6 +48,7 @@
       client_id_(client_id),
       session_id_(IntToString(session_id)),
       locked_(false),
+      doc_(NULL),
       buffer_(NULL),
       writer_(NULL),
       num_events_(0) {
@@ -54,7 +56,11 @@
   buffer_ = xmlBufferCreate();
   DCHECK(buffer_);
 
-  writer_ = xmlNewTextWriterMemory(buffer_, 0);
+  #if defined(OS_CHROMEOS)
+    writer_ = xmlNewTextWriterDoc(&doc_, /* compression */ 0);
+  #else
+    writer_ = xmlNewTextWriterMemory(buffer_, /* compression */ 0);
+  #endif  // OS_CHROMEOS
   DCHECK(writer_);
 
   int result = xmlTextWriterSetIndent(writer_, 2);
@@ -69,11 +75,15 @@
 }
 
 MetricsLogBase::~MetricsLogBase() {
+  FreeDocWriter();
+
   if (writer_)
     xmlFreeTextWriter(writer_);
 
-  if (buffer_)
+  if (buffer_) {
     xmlBufferFree(buffer_);
+    buffer_ = NULL;
+  }
 }
 
 void MetricsLogBase::CloseLog() {
@@ -85,6 +95,27 @@
 
   result = xmlTextWriterFlush(writer_);
   DCHECK_GE(result, 0);
+
+#if defined(OS_CHROMEOS)
+  xmlNodePtr root = xmlDocGetRootElement(doc_);
+  if (!hardware_class_.empty()) {
+    // The hardware class is determined after the first ongoing log is
+    // constructed, so this adds the root element's "hardwareclass"
+    // attribute when the log is closed instead.
+    xmlNewProp(root, UnsignedChar("hardwareclass"),
+               UnsignedChar(hardware_class_.c_str()));
+  }
+
+  // Flattens the XML tree into a character buffer.
+  PerfTimer dump_timer;
+  result = xmlNodeDump(buffer_, doc_, root, /* level */ 0, /* format */ 1);
+  DCHECK_GE(result, 0);
+  UMA_HISTOGRAM_TIMES("UMA.XMLNodeDumpTime", dump_timer.Elapsed());
+
+  PerfTimer free_timer;
+  FreeDocWriter();
+  UMA_HISTOGRAM_TIMES("UMA.XMLWriterDestructionTime", free_timer.Elapsed());
+#endif  // OS_CHROMEOS
 }
 
 int MetricsLogBase::GetEncodedLogSize() {
@@ -286,6 +317,18 @@
   }
 }
 
+void MetricsLogBase::FreeDocWriter() {
+  if (writer_) {
+    xmlFreeTextWriter(writer_);
+    writer_ = NULL;
+  }
+
+  if (doc_) {
+    xmlFreeDoc(doc_);
+    doc_ = NULL;
+  }
+}
+
 void MetricsLogBase::StartElement(const char* name) {
   DCHECK(!locked_);
   DCHECK(name);