Cleanup some unncessary dependencies on libxml.

As working on change committed in rev50132, instead of yet adding another project to the dependency list of libxml, I decided to abstract the dependency in the metrics helper.

BUG=0
TEST=None

Review URL: http://codereview.chromium.org/2753010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@50952 0039d316-1c4b-4281-b951-d872f2087c98

8 files changed, 84 insertions, 62 deletions

diff --git a/chrome/browser/metrics/metrics_service.cc b/chrome/browser/metrics/metrics_service.cc
index 21c1789..c158226 100644
--- a/chrome/browser/metrics/metrics_service.cc
+++ b/chrome/browser/metrics/metrics_service.cc
@@ -187,6 +187,7 @@
 #include "chrome/common/pref_names.h"
 #include "chrome/common/render_messages.h"
 #include "webkit/glue/plugins/plugin_list.h"
+#include "libxml/xmlwriter.h"
 
 #if !defined(OS_WIN)
 #include "base/rand_util.h"
@@ -700,7 +701,7 @@ void MetricsService::InitializeMetricsState() {
 
   // Initialize uptime counters.
   int64 startup_uptime = MetricsLog::GetIncrementalUptime(pref);
-  DCHECK(0 == startup_uptime);
+  DCHECK_EQ(0, startup_uptime);
   // For backwards compatibility, leave this intact in case Omaha is checking
   // them.  prefs::kStabilityLastTimestampSec may also be useless now.
   // TODO(jar): Delete these if they have no uses.
diff --git a/chrome/browser/metrics/metrics_service.h b/chrome/browser/metrics/metrics_service.h
index 016640d..de6b6ba 100644
--- a/chrome/browser/metrics/metrics_service.h
+++ b/chrome/browser/metrics/metrics_service.h
@@ -36,6 +36,12 @@ class HistogramSynchronizer;
 class PrefService;
 class TemplateURLModel;
 
+// Forward declaration of the xmlNode to avoid having tons of gyp files
+// needing to depend on the libxml third party lib.
+struct _xmlNode;
+typedef struct _xmlNode xmlNode;
+typedef xmlNode* xmlNodePtr;
+
 // This is used to quickly log stats from child process related notifications in
 // MetricsService::child_stats_buffer_.  The buffer's contents are transferred
 // out when Local State is periodically saved.  The information is then
diff --git a/chrome/chrome.gyp b/chrome/chrome.gyp
index b609d73..0c6726d 100644
--- a/chrome/chrome.gyp
+++ b/chrome/chrome.gyp
@@ -569,7 +569,6 @@
         '../skia/skia.gyp:skia',
         '../third_party/icu/icu.gyp:icui18n',
         '../third_party/icu/icu.gyp:icuuc',
-        '../third_party/libxml/libxml.gyp:libxml',
         '../third_party/npapi/npapi.gyp:npapi',
         '../third_party/hunspell/hunspell.gyp:hunspell',
         '../webkit/support/webkit_support.gyp:glue',
@@ -1591,7 +1590,6 @@
             '../third_party/icu/icu.gyp:*',
             '../third_party/libjpeg/libjpeg.gyp:*',
             '../third_party/libpng/libpng.gyp:*',
-            '../third_party/libxml/libxml.gyp:*',
             '../third_party/libxslt/libxslt.gyp:*',
             '../third_party/lzma_sdk/lzma_sdk.gyp:*',
             '../third_party/modp_b64/modp_b64.gyp:*',
diff --git a/chrome/chrome_installer_util.gypi b/chrome/chrome_installer_util.gypi
index f36a559..a7dac66 100644
--- a/chrome/chrome_installer_util.gypi
+++ b/chrome/chrome_installer_util.gypi
@@ -80,7 +80,6 @@
             '<(DEPTH)/third_party/bspatch/bspatch.gyp:bspatch',
             '<(DEPTH)/third_party/icu/icu.gyp:icui18n',
             '<(DEPTH)/third_party/icu/icu.gyp:icuuc',
-            '<(DEPTH)/third_party/libxml/libxml.gyp:libxml',
             '<(DEPTH)/third_party/lzma_sdk/lzma_sdk.gyp:lzma_sdk',
           ],
           'sources': [
diff --git a/chrome/chrome_tests.gypi b/chrome/chrome_tests.gypi
index 3c4ba96..10c8633 100644
--- a/chrome/chrome_tests.gypi
+++ b/chrome/chrome_tests.gypi
@@ -464,7 +464,6 @@
         '../testing/gtest.gyp:gtest',
         '../third_party/icu/icu.gyp:icui18n',
         '../third_party/icu/icu.gyp:icuuc',
-        '../third_party/libxml/libxml.gyp:libxml',
       ],
       'include_dirs': [
         '..',
@@ -1984,7 +1983,6 @@
         '../testing/gtest.gyp:gtest',
         '../third_party/icu/icu.gyp:icui18n',
         '../third_party/icu/icu.gyp:icuuc',
-        '../third_party/libxml/libxml.gyp:libxml',
         '../third_party/npapi/npapi.gyp:npapi',
         '../third_party/WebKit/WebKit/chromium/WebKit.gyp:webkit',
       ],
@@ -2094,7 +2092,6 @@
         'test_support_ui',
         '../skia/skia.gyp:skia',
         '../testing/gtest.gyp:gtest',
-        '../third_party/libxml/libxml.gyp:libxml',
         '../third_party/libxslt/libxslt.gyp:libxslt',
         '../third_party/npapi/npapi.gyp:npapi',
       ],
diff --git a/chrome/common/metrics_helpers.cc b/chrome/common/metrics_helpers.cc
index 99cda5a..68f9083 100644
--- a/chrome/common/metrics_helpers.cc
+++ b/chrome/common/metrics_helpers.cc
@@ -23,6 +23,7 @@
 #include "base/third_party/nspr/prtime.h"
 #include "chrome/common/logging_chrome.h"
 #include "googleurl/src/gurl.h"
+#include "libxml/xmlwriter.h"
 
 #define OPEN_ELEMENT_FOR_SCOPE(name) ScopedElement scoped_element(this, name)
 
@@ -34,67 +35,98 @@ using base::TimeDelta;
 extern "C" IMAGE_DOS_HEADER __ImageBase;
 #endif
 
-// static
-std::string MetricsLogBase::version_extension_;
+namespace {
 
 // libxml take xmlChar*, which is unsigned char*
 inline const unsigned char* UnsignedChar(const char* input) {
   return reinterpret_cast<const unsigned char*>(input);
 }
 
+}  // namespace
+
+class MetricsLogBase::XmlWrapper {
+ public:
+  XmlWrapper()
+      : doc_(NULL),
+        buffer_(NULL),
+        writer_(NULL) {
+    buffer_ = xmlBufferCreate();
+    DCHECK(buffer_);
+
+    #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);
+    DCHECK_EQ(0, result);
+  }
+
+  ~XmlWrapper() {
+    FreeDocWriter();
+    if (buffer_) {
+      xmlBufferFree(buffer_);
+      buffer_ = NULL;
+    }
+  }
+
+  void FreeDocWriter() {
+    if (writer_) {
+      xmlFreeTextWriter(writer_);
+      writer_ = NULL;
+    }
+    if (doc_) {
+      xmlFreeDoc(doc_);
+      doc_ = NULL;
+    }
+  }
+
+  xmlDocPtr doc() const { return doc_; }
+  xmlTextWriterPtr writer() const { return writer_; }
+  xmlBufferPtr buffer() const { return buffer_; }
+
+ private:
+  xmlDocPtr doc_;
+  xmlBufferPtr buffer_;
+  xmlTextWriterPtr writer_;
+};
+
+// static
+std::string MetricsLogBase::version_extension_;
+
 MetricsLogBase::MetricsLogBase(const std::string& client_id, int session_id,
                                const std::string& version_string)
     : start_time_(Time::Now()),
       client_id_(client_id),
       session_id_(IntToString(session_id)),
       locked_(false),
-      doc_(NULL),
-      buffer_(NULL),
-      writer_(NULL),
+      xml_wrapper_(new XmlWrapper),
       num_events_(0) {
 
-  buffer_ = xmlBufferCreate();
-  DCHECK(buffer_);
-
-  #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);
-  DCHECK_EQ(0, result);
-
   StartElement("log");
   WriteAttribute("clientid", client_id_);
   WriteInt64Attribute("buildtime", GetBuildTime());
   WriteAttribute("appversion", version_string);
-
-  DCHECK_GE(result, 0);
 }
 
 MetricsLogBase::~MetricsLogBase() {
-  FreeDocWriter();
-
-  if (buffer_) {
-    xmlBufferFree(buffer_);
-    buffer_ = NULL;
-  }
+  delete xml_wrapper_;
 }
 
 void MetricsLogBase::CloseLog() {
   DCHECK(!locked_);
   locked_ = true;
 
-  int result = xmlTextWriterEndDocument(writer_);
+  int result = xmlTextWriterEndDocument(xml_wrapper_->writer());
   DCHECK_GE(result, 0);
 
-  result = xmlTextWriterFlush(writer_);
+  result = xmlTextWriterFlush(xml_wrapper_->writer());
   DCHECK_GE(result, 0);
 
 #if defined(OS_CHROMEOS)
-  xmlNodePtr root = xmlDocGetRootElement(doc_);
+  xmlNodePtr root = xmlDocGetRootElement(xml_wrapper_->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"
@@ -105,19 +137,20 @@ void MetricsLogBase::CloseLog() {
 
   // Flattens the XML tree into a character buffer.
   PerfTimer dump_timer;
-  result = xmlNodeDump(buffer_, doc_, root, /* level */ 0, /* format */ 1);
+  result = xmlNodeDump(xml_wrapper_->buffer(), xml_wrapper_->doc(),
+                       root, /* level */ 0, /* format */ 1);
   DCHECK_GE(result, 0);
   UMA_HISTOGRAM_TIMES("UMA.XMLNodeDumpTime", dump_timer.Elapsed());
 
   PerfTimer free_timer;
-  FreeDocWriter();
+  xml_wrapper_->FreeDocWriter();
   UMA_HISTOGRAM_TIMES("UMA.XMLWriterDestructionTime", free_timer.Elapsed());
 #endif  // OS_CHROMEOS
 }
 
 int MetricsLogBase::GetEncodedLogSize() {
   DCHECK(locked_);
-  return buffer_->use;
+  return xml_wrapper_->buffer()->use;
 }
 
 bool MetricsLogBase::GetEncodedLog(char* buffer, int buffer_size) {
@@ -125,13 +158,13 @@ bool MetricsLogBase::GetEncodedLog(char* buffer, int buffer_size) {
   if (buffer_size < GetEncodedLogSize())
     return false;
 
-  memcpy(buffer, buffer_->content, GetEncodedLogSize());
+  memcpy(buffer, xml_wrapper_->buffer()->content, GetEncodedLogSize());
   return true;
 }
 
 std::string MetricsLogBase::GetEncodedLogString() {
   DCHECK(locked_);
-  return std::string(reinterpret_cast<char*>(buffer_->content));
+  return std::string(reinterpret_cast<char*>(xml_wrapper_->buffer()->content));
 }
 
 int MetricsLogBase::GetElapsedSeconds() {
@@ -285,7 +318,7 @@ void MetricsLogBase::WriteAttribute(const std::string& name,
   DCHECK(!locked_);
   DCHECK(!name.empty());
 
-  int result = xmlTextWriterWriteAttribute(writer_,
+  int result = xmlTextWriterWriteAttribute(xml_wrapper_->writer(),
                                            UnsignedChar(name.c_str()),
                                            UnsignedChar(value.c_str()));
   DCHECK_GE(result, 0);
@@ -314,30 +347,19 @@ const char* MetricsLogBase::WindowEventTypeToString(WindowEventType type) {
   }
 }
 
-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);
 
-  int result = xmlTextWriterStartElement(writer_, UnsignedChar(name));
+  int result = xmlTextWriterStartElement(xml_wrapper_->writer(),
+                                         UnsignedChar(name));
   DCHECK_GE(result, 0);
 }
 
 void MetricsLogBase::EndElement() {
   DCHECK(!locked_);
 
-  int result = xmlTextWriterEndElement(writer_);
+  int result = xmlTextWriterEndElement(xml_wrapper_->writer());
   DCHECK_GE(result, 0);
 }
 
diff --git a/chrome/common/metrics_helpers.h b/chrome/common/metrics_helpers.h
index 61f3d70..6d8b27e 100644
--- a/chrome/common/metrics_helpers.h
+++ b/chrome/common/metrics_helpers.h
@@ -17,8 +17,6 @@
 #include "base/time.h"
 #include "chrome/common/page_transition_types.h"
 
-#include "libxml/xmlwriter.h"
-
 class GURL;
 class MetricsLog;
 
@@ -105,6 +103,8 @@ class MetricsLogBase {
   }
 
  protected:
+  class XmlWrapper;
+
   // Returns a string containing the current time.
   // Virtual so that it can be overridden for testing.
   virtual std::string GetCurrentTimeString();
@@ -165,9 +165,9 @@ class MetricsLogBase {
   // not a real lock.
   bool locked_;
 
-  xmlDocPtr doc_;
-  xmlBufferPtr buffer_;
-  xmlTextWriterPtr writer_;
+  // Isolated to limit the dependency on the XML library for our consumers.
+  XmlWrapper* xml_wrapper_;
+
   int num_events_;  // the number of events recorded in this log
 
   DISALLOW_COPY_AND_ASSIGN(MetricsLogBase);
diff --git a/chrome/test/interactive_ui/interactive_ui_tests.gypi b/chrome/test/interactive_ui/interactive_ui_tests.gypi
index a7f1a8d..65cec5f 100644
--- a/chrome/test/interactive_ui/interactive_ui_tests.gypi
+++ b/chrome/test/interactive_ui/interactive_ui_tests.gypi
@@ -17,7 +17,6 @@
     '<(DEPTH)/skia/skia.gyp:skia',
     '<(DEPTH)/third_party/icu/icu.gyp:icui18n',
     '<(DEPTH)/third_party/libpng/libpng.gyp:libpng',
-    '<(DEPTH)/third_party/libxml/libxml.gyp:libxml',
     '<(DEPTH)/third_party/zlib/zlib.gyp:zlib',
     '<(DEPTH)/testing/gtest.gyp:gtest',
     '<(DEPTH)/third_party/npapi/npapi.gyp:npapi',