QUIC - Track the reason for sending InchoateClientHello in UMA

histogram.

Possible reasons are: no/empty server config, expired server config,
invalid server config and corrupted server config.

R=rch@chromium.org, asvitkine@chromium.org

Review URL: https://codereview.chromium.org/416983005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@285765 0039d316-1c4b-4281-b951-d872f2087c98

net/quic/crypto/quic_crypto_client_config.cc

@@ -4,6 +4,7 @@
 
 #include "net/quic/crypto/quic_crypto_client_config.h"
 
+#include "base/metrics/histogram.h"
 #include "base/metrics/sparse_histogram.h"
 #include "base/stl_util.h"
 #include "base/strings/string_util.h"
@@ -29,6 +30,30 @@ using std::vector;
 
 namespace net {
 
+namespace {
+
+enum ServerConfigState {
+  // WARNING: Do not change the numerical values of any of server config state.
+  // Do not remove deprecated server config states - just comment them as
+  // deprecated.
+  SERVER_CONFIG_EMPTY = 0,
+  SERVER_CONFIG_INVALID = 1,
+  SERVER_CONFIG_CORRUPTED = 2,
+  SERVER_CONFIG_EXPIRED = 3,
+
+  // NOTE: Add new server config states only immediately above this line. Make
+  // sure to update the QuicServerConfigState enum in
+  // tools/metrics/histograms/histograms.xml accordingly.
+  SERVER_CONFIG_COUNT
+};
+
+void RecordServerConfigState(ServerConfigState server_config_state) {
+  UMA_HISTOGRAM_ENUMERATION("Net.QuicClientHelloServerConfigState",
+                            server_config_state, SERVER_CONFIG_COUNT);
+}
+
+}  // namespace
+
 QuicCryptoClientConfig::QuicCryptoClientConfig()
     : disable_ecdsa_(false) {}
 
@@ -43,7 +68,13 @@ QuicCryptoClientConfig::CachedState::CachedState()
 QuicCryptoClientConfig::CachedState::~CachedState() {}
 
 bool QuicCryptoClientConfig::CachedState::IsComplete(QuicWallTime now) const {
-  if (server_config_.empty() || !server_config_valid_) {
+  if (server_config_.empty()) {
+    RecordServerConfigState(SERVER_CONFIG_EMPTY);
+    return false;
+  }
+
+  if (!server_config_valid_) {
+    RecordServerConfigState(SERVER_CONFIG_INVALID);
     return false;
   }
 
@@ -51,12 +82,14 @@ bool QuicCryptoClientConfig::CachedState::IsComplete(QuicWallTime now) const {
   if (!scfg) {
     // Should be impossible short of cache corruption.
     DCHECK(false);
+    RecordServerConfigState(SERVER_CONFIG_CORRUPTED);
     return false;
   }
 
   uint64 expiry_seconds;
   if (scfg->GetUint64(kEXPY, &expiry_seconds) != QUIC_NO_ERROR ||
       now.ToUNIXSeconds() >= expiry_seconds) {
+    RecordServerConfigState(SERVER_CONFIG_EXPIRED);
     return false;
   }
 

tools/metrics/histograms/histograms.xml

@@ -14964,6 +14964,15 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="Net.QuicClientHelloServerConfigState"
+    enum="QuicServerConfigState">
+  <owner>rtenneti@chromium.org</owner>
+  <summary>
+    The reason (the state of the server config) for sending InchoateClientHello
+    to the server.
+  </summary>
+</histogram>
+
 <histogram name="Net.QuicEphemeralPortsSuggested">
   <owner>rch@chromium.org</owner>
   <summary>The number of ports suggested per server.</summary>
@@ -45974,6 +45983,13 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   <int value="6" label="CANCELLED"/>
 </enum>
 
+<enum name="QuicServerConfigState" type="int">
+  <int value="0" label="SERVER_CONFIG_EMPTY"/>
+  <int value="1" label="SERVER_CONFIG_INVALID"/>
+  <int value="2" label="SERVER_CONFIG_CORRUPTED"/>
+  <int value="3" label="SERVER_CONFIG_EXPIRED"/>
+</enum>
+
 <enum name="QuicSessionErrorCodes" type="int">
   <int value="0" label="CONNECTING_SOCKET"/>
   <int value="1" label="SETTING_RECEIVE_BUFFER"/>