Don't use whitespace in ChannelName() under Windows Official DCHECK.

Using whitespace breaks ExtensionUpdater query parameter generation.

Bug: 832728
Change-Id: I191d175d623803d4655d22caf422bf7127bdc57c
Reviewed-on: https://chromium-review.googlesource.com/1016138Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Commit-Queue: Wez <wez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#552942}

chrome/common/channel_info_win.cc

@@ -17,7 +17,7 @@ std::string GetChannelName() {
 #if defined(DCHECK_IS_CONFIGURABLE)
   // Adorn the channel when DCHECKs are baked into the build, as there will be
   // a performance hit. See https://crbug.com/812058 for details.
-  channel += L" DCheck";
+  channel += L"-dcheck";
 #endif
   return base::UTF16ToASCII(channel);
 #else