Fix: variations service not processing studies on ChromeOS.

This is caused by not setting chrome channel before initializing FeatureList in
early startup, which was introduced in CL (https://crbug.com/1173163). In this
CL, we make GetChannel() call the SetChannel() if the channel hasn't been set
yet.

Bug: 896416
Change-Id: Id89c199779074d762f1d16edc711fedaaab66694
Reviewed-on: https://chromium-review.googlesource.com/c/1287850
Commit-Queue: Xi Han <hanxi@chromium.org>
Reviewed-by: Robert Kaplow (sloooow) <rkaplow@chromium.org>
Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Cr-Commit-Position: refs/heads/master@{#601119}

chrome/browser/chromeos/chrome_browser_main_chromeos.cc

@@ -550,13 +550,6 @@ int ChromeBrowserMainPartsChromeos::PreEarlyInitialization() {
                         .value();
   }
 
-#if defined(GOOGLE_CHROME_BUILD)
-  const char kChromeOSReleaseTrack[] = "CHROMEOS_RELEASE_TRACK";
-  std::string channel;
-  if (base::SysInfo::GetLsbReleaseValue(kChromeOSReleaseTrack, &channel))
-    chrome::SetChannel(channel);
-#endif
-
   if (!is_dbus_initialized_)
     PreEarlyInitDBus();
 

chrome/common/channel_info.h

@@ -44,11 +44,6 @@ version_info::Channel GetChannel();
 version_info::Channel GetChannelByName(const std::string& channel);
 #endif
 
-#if defined(OS_CHROMEOS)
-// Sets channel before use.
-void SetChannel(const std::string& channel);
-#endif
-
 #if defined(OS_POSIX) && defined(GOOGLE_CHROME_BUILD)
 // Returns a channel-specific suffix to use when constructing the path of the
 // default user data directory, allowing multiple channels to run side-by-side.

chrome/common/channel_info_chromeos.cc

@@ -4,11 +4,32 @@
 
 #include "chrome/common/channel_info.h"
 
+#include "base/sys_info.h"
 #include "components/version_info/version_info.h"
 
 namespace chrome {
+namespace {
 
-static version_info::Channel chromeos_channel = version_info::Channel::UNKNOWN;
+version_info::Channel chromeos_channel = version_info::Channel::UNKNOWN;
+
+#if defined(GOOGLE_CHROME_BUILD)
+// Sets the |chromeos_channel|.
+void SetChannel(const std::string& channel) {
+  if (channel == "stable-channel") {
+    chromeos_channel = version_info::Channel::STABLE;
+  } else if (channel == "beta-channel") {
+    chromeos_channel = version_info::Channel::BETA;
+  } else if (channel == "dev-channel") {
+    chromeos_channel = version_info::Channel::DEV;
+  } else if (channel == "canary-channel") {
+    chromeos_channel = version_info::Channel::CANARY;
+  } else {
+    chromeos_channel = version_info::Channel::UNKNOWN;
+  }
+}
+#endif
+
+}  // namespace
 
 std::string GetChannelName() {
 #if defined(GOOGLE_CHROME_BUILD)
@@ -29,20 +50,20 @@ std::string GetChannelName() {
 }
 
 version_info::Channel GetChannel() {
-  return chromeos_channel;
-}
+  static bool is_channel_set = false;
+  if (is_channel_set)
+    return chromeos_channel;
 
-void SetChannel(const std::string& channel) {
-#if defined(GOOGLE_CHROME_BUILD)
-  if (channel == "stable-channel") {
-    chromeos_channel = version_info::Channel::STABLE;
-  } else if (channel == "beta-channel") {
-    chromeos_channel = version_info::Channel::BETA;
-  } else if (channel == "dev-channel") {
-    chromeos_channel = version_info::Channel::DEV;
-  } else if (channel == "canary-channel") {
-    chromeos_channel = version_info::Channel::CANARY;
+#if !defined(GOOGLE_CHROME_BUILD)
+  return version_info::Channel::UNKNOWN;
+#else
+  static const char kChromeOSReleaseTrack[] = "CHROMEOS_RELEASE_TRACK";
+  std::string channel;
+  if (base::SysInfo::GetLsbReleaseValue(kChromeOSReleaseTrack, &channel)) {
+    SetChannel(channel);
+    is_channel_set = true;
   }
+  return chromeos_channel;
 #endif
 }