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

chrome/BUILD.gn

Index: chrome/BUILD.gn
diff --git a/chrome/BUILD.gn b/chrome/BUILD.gn
index f57535907ccbb8581bb96a26e522dcd95f01c1fe..30322d3a8699fe84e979d4aa7aef01127eb565f2 100644
--- a/chrome/BUILD.gn
+++ b/chrome/BUILD.gn
@@ -242,6 +242,11 @@ group("child_dependencies") {
       "//third_party/WebKit/public:blink_devtools_frontend_resources",
     ]
   }
+  if (cld_version == 0 || cld_version == 2) {
+    deps += [
+      "//third_party/cld_2:cld2_platform_impl",
+    ]
+  }
 }
 
 if (is_win) {