Add DCHECK(is_valid()) to DMToken::value().

This DCHECK was not included to avoid causing problems with older code
that would read the value of empty tokens. Now that this code is
migrated the check can be included.

Change-Id: I1a9daff8624ba1f7e72df269636d765f2ad9ee20
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1935833Reviewed-by: Owen Min <zmin@chromium.org>
Commit-Queue: Dominique Fauteux-Chapleau <domfc@chromium.org>
Cr-Commit-Position: refs/heads/master@{#719237}

chrome/browser/policy/browser_dm_token_storage_unittest.cc

@@ -115,7 +115,7 @@ TEST_F(BrowserDMTokenStorageTest, RetrieveEnrollmentToken) {
 TEST_P(BrowserDMTokenStorageStoreAndRetrieveTest, StoreDMToken) {
   storage_.SetDMToken(GetParam().dm_token_to_store);
   DMToken dm_token = storage_.RetrieveDMToken();
-  if (GetParam().expect_valid || GetParam().expect_empty) {
+  if (GetParam().expect_valid) {
     EXPECT_EQ(GetParam().expected_retrieved_dm_token, dm_token.value());
   }
   EXPECT_EQ(GetParam().expect_valid, dm_token.is_valid());
@@ -124,7 +124,7 @@ TEST_P(BrowserDMTokenStorageStoreAndRetrieveTest, StoreDMToken) {
 
   // The DM token should be cached in memory and not read from the system again.
   storage_.SetDMToken("not_saved");
-  if (GetParam().expect_valid || GetParam().expect_empty) {
+  if (GetParam().expect_valid) {
     EXPECT_EQ(GetParam().expected_retrieved_dm_token, dm_token.value());
   }
 }
@@ -153,7 +153,7 @@ TEST_F(BrowserDMTokenStorageTest, ClearDMToken) {
 
 TEST_P(BrowserDMTokenStorageStoreAndRetrieveTest, RetrieveDMToken) {
   DMToken dm_token = storage_.RetrieveDMToken();
-  if (GetParam().expect_valid || GetParam().expect_empty) {
+  if (GetParam().expect_valid) {
     EXPECT_EQ(GetParam().expected_retrieved_dm_token, dm_token.value());
   }
   EXPECT_EQ(GetParam().expect_valid, dm_token.is_valid());

components/policy/core/common/cloud/dm_token.cc

@@ -27,7 +27,7 @@ DMToken::DMToken(Status status, const base::StringPiece value)
     : status_(status), value_(value) {}
 
 const std::string& DMToken::value() const {
-  // TODO(domfc): Add DCHECK(is_valid()) after migrating code.
+  DCHECK(is_valid());
   return value_;
 }