Use channel constants for crash telemetry initialization gating.

The use of a string literal for the channel makes it harder than it
should be to see what this is doing. Using the channel constants also
allows easy string searching for the use of the concept.

Bug: 806661
Change-Id: I1711539886f74549f4ac5db1a16108907b679bd4
Reviewed-on: https://chromium-review.googlesource.com/953071Reviewed-by: Will Harris <wfh@chromium.org>
Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Commit-Queue: Sigurður Ásgeirsson <siggi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#541835}

chrome/browser/chrome_browser_main_win.cc

@@ -52,6 +52,7 @@
 #include "chrome/browser/win/browser_util.h"
 #include "chrome/browser/win/chrome_elf_init.h"
 #include "chrome/chrome_watcher/chrome_watcher_main_api.h"
+#include "chrome/common/channel_info.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/chrome_features.h"
 #include "chrome/common/chrome_paths.h"
@@ -72,6 +73,7 @@
 #include "components/crash/content/app/crash_export_thunks.h"
 #include "components/crash/content/app/dump_hung_process_with_ptype.h"
 #include "components/crash/core/common/crash_key.h"
+#include "components/version_info/channel.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/common/content_switches.h"
@@ -493,7 +495,7 @@ int ChromeBrowserMainPartsWin::PreCreateThreads() {
   static crash_reporter::CrashKeyString<32> update_cohort_name("cohort-name");
   update_cohort_name.Set(base::UTF16ToUTF8(details.update_cohort_name()));
 
-  if (details.channel().find(L"canary") == 0) {
+  if (chrome::GetChannel() == version_info::Channel::CANARY) {
     content::RenderProcessHost::SetHungRendererAnalysisFunction(
         &DumpHungRendererProcessImpl);
   }