Add Windows 10 build number to user-agent

The build number would be added to the version string in UA
only if the major version of Windows is equal or greater than 10.
Nothing would be changed for the old version of Windows.

BUG=664622

Review-Url: https://codereview.chromium.org/2533303003
Cr-Commit-Position: refs/heads/master@{#437532}

base/sys_info_win.cc

@@ -153,7 +153,7 @@ void SysInfo::OperatingSystemVersionNumbers(int32_t* major_version,
   win::OSInfo* os_info = win::OSInfo::GetInstance();
   *major_version = os_info->version_number().major;
   *minor_version = os_info->version_number().minor;
-  *bugfix_version = 0;
+  *bugfix_version = os_info->version_number().build;
 }
 
 }  // namespace base

content/common/user_agent.cc

@@ -63,6 +63,15 @@ std::string BuildOSCpuInfo() {
 #endif
 
 #if defined(OS_WIN)
+  std::string windows_version_str;
+  if (os_major_version >= 10) {
+    base::StringAppendF(&windows_version_str, "%d.%d.%d",
+      os_major_version, os_minor_version, os_bugfix_version);
+  } else {
+    base::StringAppendF(
+      &windows_version_str, "%d.%d", os_major_version, os_minor_version);
+  }
+
   std::string architecture_token;
   base::win::OSInfo* os_info = base::win::OSInfo::GetInstance();
   if (os_info->wow64_status() == base::win::OSInfo::WOW64_ENABLED) {
@@ -108,9 +117,8 @@ std::string BuildOSCpuInfo() {
   base::StringAppendF(
       &os_cpu,
 #if defined(OS_WIN)
-      "Windows NT %d.%d%s",
-      os_major_version,
-      os_minor_version,
+      "Windows NT %s%s",
+      windows_version_str.c_str(),
       architecture_token.c_str()
 #elif defined(OS_MACOSX)
       "Intel Mac OS X %d_%d_%d",