Refactor language detection logic to allow non-static CLD data sources.

chrome/browser/component_updater/cld_component_installer.cc

Index: chrome/browser/component_updater/cld_component_installer.cc
diff --git a/chrome/browser/component_updater/cld_component_installer.cc b/chrome/browser/component_updater/cld_component_installer.cc
index a761ee6988175c3479f5dc2b5d5f4c5eff7bda11..90090763fed9f3329572805c9f327ef511fd076d 100644
--- a/chrome/browser/component_updater/cld_component_installer.cc
+++ b/chrome/browser/component_updater/cld_component_installer.cc
@@ -15,6 +15,7 @@
 #include "base/path_service.h"
 #include "components/component_updater/component_updater_paths.h"
 #include "components/translate/content/browser/browser_cld_data_provider.h"
+#include "components/translate/content/browser/browser_cld_data_provider_factory.h"
 #include "components/translate/content/common/cld_data_source.h"
 #include "content/public/browser/browser_thread.h"
 #include "net/ssl/ssl_config_service.h"
@@ -108,10 +109,11 @@ std::string CldComponentInstallerTraits::GetName() const {
 
 void RegisterCldComponent(ComponentUpdateService* cus) {
   // Make sure we don't start up if the CLD data source isn't compatible.
-  if (!translate::CldDataSource::ShouldRegisterForComponentUpdates()) {
+  if (translate::CldDataSource::Get() !=
+      translate::CldDataSource::GetComponentDataSource()) {
     // This is a serious build-time configuration error.

[picksi1, 2014/10/30 17:37:32]

The above 2 lines appear three times. Can we wrap them into a single function
e.g.

if (translate::CldDataSource::IsIncompatible()) {
....
}

[Andrew Hayden (chromium.org), 2014/10/30 17:51:13]

I don't think it's worth it. It can't just be
translate::CldDataSource::IsIncompatible() because that question can't be
answered without context: compatible *with what*? The answer here is compatible
with the component updater, but there is only one such data source and it is the
ComponentCldDataSource. Which is why I did away with the booleans we previously
passed to the CldDataSource constructor along with all those pointless private
classes.

I don't particularly mind adding another method here, I just don't think it will
actually clean anything up. There's not likely to be any more code that ever
needs this particular check, since all of the logic starts here.

     LOG(ERROR) << "Wrong CLD data source: " <<
-        translate::CldDataSource::GetName();
+        translate::CldDataSource::Get()->GetName();
     NOTREACHED();
     return;
   }
@@ -132,7 +134,7 @@ void CldComponentInstallerTraits::SetLatestCldDataFile(
     const base::FilePath& path) {
   VLOG(1) << "Setting CLD data file location: " << path.value();
   g_latest_cld_data_file.Get() = path;
-  translate::SetCldDataFilePath(path);
+  translate::CldDataSource::Get()->SetCldDataFilePath(path);
 }
 
 base::FilePath CldComponentInstallerTraits::GetLatestCldDataFile() {