Move DOM-inspecting language detection logic to Blink.

components/translate/content/renderer/translate_helper.h

Index: components/translate/content/renderer/translate_helper.h
diff --git a/components/translate/content/renderer/translate_helper.h b/components/translate/content/renderer/translate_helper.h
index e3eab899e712d5481f7dc52859eee8f303828f8d..1cfaa25a91070c9ba113ef2d8f9cdd5f345564cc 100644
--- a/components/translate/content/renderer/translate_helper.h
+++ b/components/translate/content/renderer/translate_helper.h
@@ -13,6 +13,7 @@
 #include "base/strings/string16.h"
 #include "base/time/time.h"
 #include "components/translate/content/renderer/renderer_cld_data_provider.h"
+#include "components/translate/core/common/language_detection_details.h"
 #include "components/translate/core/common/translate_errors.h"
 #include "content/public/renderer/render_frame_observer.h"
 #include "url/gurl.h"
@@ -20,6 +21,7 @@
 namespace blink {
 class WebDocument;
 class WebLocalFrame;
+struct WebLanguageDetectionDetails;
 }
 
 namespace content {
@@ -85,8 +87,10 @@ class TranslateHelper : public content::RenderFrameObserver {
                            const std::string& extension_scheme);
   ~TranslateHelper() override;
 
-  // Informs us that the page's text has been extracted.
-  void PageCaptured(const base::string16& contents);
+  // Informs us that language detection metadata has been extracted
+  // from the page.
+  void LanguageDetectionDetailsCaptured(
+      const LanguageDetectionDetails& details);
 
   // Lets the translation system know that we are preparing to navigate to
   // the specified URL. If there is anything that can or should be done before
@@ -164,8 +168,8 @@ class TranslateHelper : public content::RenderFrameObserver {
   // RenderFrameObserver implementation.
   bool OnMessageReceived(const IPC::Message& message) override;
 
-  // Informs us that the page's text has been extracted.
-  void PageCapturedImpl(int page_seq_no, const base::string16& contents);
+  // Attempt language detection.
+  void DetectLanguage(int page_seq_no);
 
   // Cancels any translation that is currently being performed.  This does not
   // revert existing translations.
@@ -227,7 +231,7 @@ class TranslateHelper : public content::RenderFrameObserver {
   bool cld_data_polling_canceled_;
 
   // Whether or not a PageCaptured event arrived prior to CLD data becoming
-  // available. If true, deferred_contents_ contains the most recent contents.
+  // available. If true, deferred_details_ contains the most recent details.
   bool deferred_page_capture_;
 
   // The ID of the page most recently reported to PageCaptured if
@@ -243,9 +247,8 @@ class TranslateHelper : public content::RenderFrameObserver {
   // The URL scheme for translate extensions.
   std::string extension_scheme_;
 
-  // The contents of the page most recently reported to PageCaptured if
-  // deferred_page_capture_ is true.
-  base::string16 deferred_contents_;
+  // The most recently reported language detection details.
+  LanguageDetectionDetails detection_details_;
 
   // Method factory used to make calls to TranslatePageImpl.
   base::WeakPtrFactory<TranslateHelper> weak_method_factory_;