Collect UMA data for Origin Trials

content/common/origin_trials/trial_token.cc

Index: content/common/origin_trials/trial_token.cc
diff --git a/content/common/origin_trials/trial_token.cc b/content/common/origin_trials/trial_token.cc
index 0a137edc68b43e780e572c1d083379c864921fc8..4e93efd89c4be2c51f33b795d24c14c3ab92d0cc 100644
--- a/content/common/origin_trials/trial_token.cc
+++ b/content/common/origin_trials/trial_token.cc
@@ -43,49 +43,64 @@ const uint8_t kVersion2 = 2;
 
 TrialToken::~TrialToken() {}
 
-// static
-std::unique_ptr<TrialToken> TrialToken::From(const std::string& token_text,
-                                             base::StringPiece public_key) {
-  std::unique_ptr<std::string> token_payload = Extract(token_text, public_key);
-  if (!token_payload) {
-    return nullptr;
+// Static
+TrialTokenStatus TrialToken::From(const std::string& token_text,
+                                  base::StringPiece public_key,
+                                  std::unique_ptr<TrialToken>& out_token) {
+  std::unique_ptr<std::string> token_payload;
+  TrialTokenStatus status = Extract(token_text, public_key, token_payload);
+  if (status != TRIAL_TOKEN_STATUS_SUCCESS) {
+    out_token.reset();
+    return status;
   }
-  return Parse(*token_payload);
+  out_token = Parse(*token_payload);
+  return out_token ? TRIAL_TOKEN_STATUS_SUCCESS : TRIAL_TOKEN_STATUS_MALFORMED;
 }
 
-bool TrialToken::IsValidForFeature(const url::Origin& origin,
-                                   base::StringPiece feature_name,
-                                   const base::Time& now) const {
-  return ValidateOrigin(origin) && ValidateFeatureName(feature_name) &&
-         ValidateDate(now);
+TrialTokenStatus TrialToken::IsValidForFeature(const url::Origin& origin,
+                                               base::StringPiece feature_name,
+                                               const base::Time& now) const {
+  // The order of these checks is intentional. For example, will only report a
+  // token as expired if it is valid for the origin + feature combination.
+  if (!ValidateOrigin(origin)) {
+    return TRIAL_TOKEN_STATUS_WRONG_ORIGIN;
+  }
+  if (!ValidateFeatureName(feature_name)) {
+    return TRIAL_TOKEN_STATUS_WRONG_FEATURE;
+  }
+  if (!ValidateDate(now)) {
+    return TRIAL_TOKEN_STATUS_EXPIRED;
+  }
+  return TRIAL_TOKEN_STATUS_SUCCESS;
 }
 
-std::unique_ptr<std::string> TrialToken::Extract(
+TrialTokenStatus TrialToken::Extract(
     const std::string& token_payload,
-    base::StringPiece public_key) {
+    base::StringPiece public_key,
+    std::unique_ptr<std::string>& out_token_json) {
   if (token_payload.empty()) {
-    return nullptr;
+    return TRIAL_TOKEN_STATUS_MALFORMED;
   }
 
   // Token is base64-encoded; decode first.
   std::string token_contents;
   if (!base::Base64Decode(token_payload, &token_contents)) {
-    return nullptr;
+    return TRIAL_TOKEN_STATUS_MALFORMED;
   }
 
   // Only version 2 currently supported.
   if (token_contents.length() < (kVersionOffset + kVersionSize)) {
-    return nullptr;
+    return TRIAL_TOKEN_STATUS_MALFORMED;
   }
   uint8_t version = token_contents[kVersionOffset];
   if (version != kVersion2) {
-    return nullptr;
+    return TRIAL_TOKEN_STATUS_MALFORMED;
   }
 
   // Token must be large enough to contain a version, signature, and payload
   // length.
   if (token_contents.length() < (kPayloadLengthOffset + kPayloadLengthSize)) {
-    return nullptr;
+    return TRIAL_TOKEN_STATUS_MALFORMED;
   }
 
   // Extract the length of the signed data (Big-endian).
@@ -94,7 +109,7 @@ std::unique_ptr<std::string> TrialToken::Extract(
 
   // Validate that the stated length matches the actual payload length.
   if (payload_length != token_contents.length() - kPayloadOffset) {
-    return nullptr;
+    return TRIAL_TOKEN_STATUS_MALFORMED;
   }
 
   // Extract the version-specific contents of the token.
@@ -110,12 +125,13 @@ std::unique_ptr<std::string> TrialToken::Extract(
 
   // Validate the signature on the data before proceeding.
   if (!TrialToken::ValidateSignature(signature, signed_data, public_key)) {
-    return nullptr;
+    return TRIAL_TOKEN_STATUS_INVALID_SIGNATURE;
   }
 
   // Return just the payload, as a new string.
-  return base::WrapUnique(
+  out_token_json.reset(
       new std::string(token_contents, kPayloadOffset, payload_length));
+  return TRIAL_TOKEN_STATUS_SUCCESS;
 }
 
 std::unique_ptr<TrialToken> TrialToken::Parse(const std::string& token_json) {