Move ranker_model_loader to a new component.

components/machine_intelligence/ranker_model_loader.h

Index: components/machine_intelligence/ranker_model_loader.h
diff --git a/components/translate/core/browser/ranker_model_loader.h b/components/machine_intelligence/ranker_model_loader.h
similarity index 86%
rename from components/translate/core/browser/ranker_model_loader.h
rename to components/machine_intelligence/ranker_model_loader.h
index 68445b74ecd8a13547d1a324f60409e44385bbe9..60afa10fc8b49a1573621584e30bafe9a5245ac8 100644
--- a/components/translate/core/browser/ranker_model_loader.h
+++ b/components/machine_intelligence/ranker_model_loader.h
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef COMPONENTS_TRANSLATE_CORE_BROWSER_RANKER_MODEL_LOADER_H_
-#define COMPONENTS_TRANSLATE_CORE_BROWSER_RANKER_MODEL_LOADER_H_
+#ifndef COMPONENTS_MACHINE_INTELLIGENCE_RANKER_MODEL_LOADER_H_
+#define COMPONENTS_MACHINE_INTELLIGENCE_RANKER_MODEL_LOADER_H_
 
 #include <memory>
 #include <string>
@@ -14,19 +14,17 @@
 #include "base/memory/weak_ptr.h"
 #include "base/sequence_checker.h"
 #include "base/time/time.h"
+#include "net/url_request/url_request_context_getter.h"
 #include "url/gurl.h"
 
 namespace base {
 class SequencedTaskRunner;
 }  // namespace base
 
-namespace chrome_intelligence {
-class RankerModel;
-}  // namespace chrome_intelligence
-
-namespace translate {
+namespace machine_intelligence {
 
-class TranslateURLFetcher;
+class RankerURLFetcher;
+class RankerModel;
 
 // Enumeration denoting the outcome of an attempt to download the model. This
 // must be kept in sync with the RankerModelStatus enum in histograms.xml
@@ -44,8 +42,8 @@ enum class RankerModelStatus {
   MAX
 };
 
-// If enabled, downloads a translate ranker model and uses it to determine
-// whether the user should be given a translation prompt or not.
+// Loads a ranker model. Will attempt to load the model from disk cache. If it
+// fails, will attempt to download from the given URL.
 class RankerModelLoader {
  public:
   // Callback to validate a ranker model on behalf of the model loader client.
@@ -53,13 +51,13 @@ class RankerModelLoader {
   // the features generated when ranking translation offerings.  This will be
   // called on the sequence on which the model loader was constructed.
   using ValidateModelCallback = base::RepeatingCallback<RankerModelStatus(
-      const chrome_intelligence::RankerModel&)>;
+      const machine_intelligence::RankerModel&)>;
 
   // Called to transfer ownership of a loaded model back to the model loader
   // client. This will be called on the sequence on which the model loader was
   // constructed.
   using OnModelAvailableCallback = base::RepeatingCallback<void(
-      std::unique_ptr<chrome_intelligence::RankerModel>)>;
+      std::unique_ptr<machine_intelligence::RankerModel>)>;
 
   // |validate_model_callback| may be called on any sequence; it must be thread
   // safe.
@@ -80,6 +78,7 @@ class RankerModelLoader {
   // generated by this loader.
   RankerModelLoader(ValidateModelCallback validate_model_callback,
                     OnModelAvailableCallback on_model_available_callback,
+                    net::URLRequestContextGetter* request_context_getter,
                     base::FilePath model_path,
                     GURL model_url,
                     std::string uma_prefix);
@@ -130,15 +129,14 @@ class RankerModelLoader {
 
   // Called when |url_fetcher_| has finished loading |data| from |model_url_|.
   //
-  // This call signature is mandated by TranslateURLFetcher.
+  // This call signature is mandated by RankerURLFetcher.
   //
-  // id - the id given to the TranslateURLFetcher on creation
   // success - true of the download was successful
   // data - the body of the downloads response
-  void OnURLFetched(int id, bool success, const std::string& data);
+  void OnURLFetched(bool success, const std::string& data);
 
   // Parse |data| and return a validated model. Returns nullptr on failure.
-  std::unique_ptr<chrome_intelligence::RankerModel> CreateAndValidateModel(
+  std::unique_ptr<machine_intelligence::RankerModel> CreateAndValidateModel(
       const std::string& data);
 
   // Helper function to log |model_status| to UMA and return it.
@@ -146,7 +144,7 @@ class RankerModelLoader {
 
   // Validates that ranker model loader tasks are all performed on the same
   // sequence.
-  base::SequenceChecker sequence_checker_;
+  SEQUENCE_CHECKER(sequence_checker_);
 
   // The task runner on which background tasks are performed.
   const scoped_refptr<base::SequencedTaskRunner> background_task_runner_;
@@ -160,6 +158,9 @@ class RankerModelLoader {
   // constructed.
   const OnModelAvailableCallback on_model_available_cb_;
 
+  // Request Context Getter used for RankerURLFetcher.
+  scoped_refptr<net::URLRequestContextGetter> request_context_getter_;
+
   // The path at which the model is (or should be) cached.
   const base::FilePath model_path_;
 
@@ -171,7 +172,7 @@ class RankerModelLoader {
   const std::string uma_prefix_;
 
   // Used to download model data from |model_url_|.
-  std::unique_ptr<TranslateURLFetcher> url_fetcher_;
+  std::unique_ptr<RankerURLFetcher> url_fetcher_;
 
   // The next time before which no new attempts to download the model should be
   // attempted.
@@ -190,6 +191,6 @@ class RankerModelLoader {
   DISALLOW_COPY_AND_ASSIGN(RankerModelLoader);
 };
 
-}  // namespace translate
+}  // namespace machine_intelligence
 
-#endif  // COMPONENTS_TRANSLATE_CORE_BROWSER_RANKER_MODEL_LOADER_H_
+#endif  // COMPONENTS_MACHINE_INTELLIGENCE_RANKER_MODEL_LOADER_H_