Revert "Enable lacros on stable channel."

This reverts commit da75e6c8.

Reason for revert: No longer want this functionality.

Original change's description:
> Enable lacros on stable channel.
> 
> Change-Id: I3a3efe60a3b53bbd6f431a257bbf8e6266f903e8
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2377067
> Commit-Queue: Erik Chen <erikchen@chromium.org>
> Auto-Submit: Erik Chen <erikchen@chromium.org>
> Reviewed-by: Hidehiko Abe <hidehiko@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#801861}

TBR=erikchen@chromium.org,hidehiko@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Change-Id: I8e5affae1020f948b3b18be3af858fd9ba052a91
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2388345Reviewed-by: James Cook <jamescook@chromium.org>
Commit-Queue: James Cook <jamescook@chromium.org>
Auto-Submit: Erik Chen <erikchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#803607}

chrome/browser/chromeos/crosapi/browser_util.cc

@@ -82,12 +82,13 @@ bool IsLacrosAllowed(Channel channel) {
       return true;
     case Channel::CANARY:
     case Channel::DEV:
-    case Channel::BETA:
-    case Channel::STABLE: {
+    case Channel::BETA: {
       std::string canonical_email = user->GetAccountId().GetUserEmail();
       return base::EndsWith(canonical_email, "google.com",
                             base::CompareCase::INSENSITIVE_ASCII);
     }
+    case Channel::STABLE:
+      return false;
   }
 }
 

chrome/browser/chromeos/crosapi/browser_util_unittest.cc

@@ -57,7 +57,11 @@ TEST_F(LacrosUtilTest, AllowedForGoogler) {
   EXPECT_TRUE(browser_util::IsLacrosAllowed(Channel::CANARY));
   EXPECT_TRUE(browser_util::IsLacrosAllowed(Channel::DEV));
   EXPECT_TRUE(browser_util::IsLacrosAllowed(Channel::BETA));
-  EXPECT_TRUE(browser_util::IsLacrosAllowed(Channel::STABLE));
+}
+
+TEST_F(LacrosUtilTest, BlockedForGoogler) {
+  AddRegularUser("user@google.com");
+  EXPECT_FALSE(browser_util::IsLacrosAllowed(Channel::STABLE));
 }
 
 TEST_F(LacrosUtilTest, BlockedForChildUser) {