[TFLite] Fix test for windows and create custom resolver.

This fixes some path and test data issues that cause tests to fail
when enabling TFLite in the build.

This also creates a TFLite resolver for Chrome with the set of ops
to be supported initially.

Bug: 1165517
Change-Id: Ib0acdcb380578e94f4b7172b5ebe27ab6faafc25
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2631186Reviewed-by: Colin Blundell <blundell@chromium.org>
Reviewed-by: Sophie Chang <sophiechang@chromium.org>
Commit-Queue: Michael Crouse <mcrouse@chromium.org>
Cr-Commit-Position: refs/heads/master@{#844164}

chrome/browser/BUILD.gn

@@ -2468,7 +2468,7 @@ static_library("browser") {
       "tflite_experiment/tflite_experiment_switches.h",
     ]
 
-    deps += [ "//chrome/services/machine_learning" ]
+    public_deps += [ "//chrome/services/machine_learning" ]
   }
 
   # Platforms that have a network diagnostics dialog. All others fall through

chrome/browser/tflite_experiment/tflite_experiment_keyed_service_browsertest.cc

@@ -5,6 +5,7 @@
 #include "chrome/browser/tflite_experiment/tflite_experiment_keyed_service.h"
 
 #include "base/command_line.h"
+#include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/json/json_reader.h"
 #include "base/path_service.h"
@@ -25,9 +26,7 @@
 #include "content/public/test/browser_test_utils.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
-constexpr char kTFLiteModelName[] = "simple_test.tflite";
 constexpr char kNavigationURL[] = "https://google.com";
-constexpr char kTFLiteExperimentLogName[] = "tflite_experiment.log";
 
 namespace {
 // Fetch and calculate the total number of samples from all the bins for
@@ -90,16 +89,6 @@ IN_PROC_BROWSER_TEST_F(TFLiteExperimentKeyedServiceDisabledBrowserTest,
   EXPECT_FALSE(tflite_experiment_keyed_service->tflite_predictor());
 }
 
-IN_PROC_BROWSER_TEST_F(
-    TFLiteExperimentKeyedServiceDisabledBrowserTest,
-    TFLiteExperimentEnabledButTFLitePredictorDisabledOnNavigation) {
-  GURL navigation_url(kNavigationURL);
-  ui_test_utils::NavigateToURL(browser(), navigation_url);
-  WaitForTFLiteObserverToCallNullTFLitePredictor();
-  histogram_tester()->ExpectUniqueSample(
-      "TFLiteExperiment.Observer.TFLitePredictor.Null", true, 1);
-}
-
 class TFLiteExperimentKeyedServiceBrowserTest : public InProcessBrowserTest {
  public:
   TFLiteExperimentKeyedServiceBrowserTest() = default;
@@ -112,21 +101,21 @@ class TFLiteExperimentKeyedServiceBrowserTest : public InProcessBrowserTest {
     // Set TFLite model path.
     base::PathService::Get(chrome::DIR_TEST_DATA, &g_test_data_directory);
     g_test_data_directory =
-        g_test_data_directory.Append(FILE_PATH_LITERAL(kTFLiteModelName));
+        g_test_data_directory.Append(FILE_PATH_LITERAL("simple_test.tflite"));
     cmd->AppendSwitchASCII(tflite_experiment::switches::kTFLiteModelPath,
-                           g_test_data_directory.value());
+                           g_test_data_directory.MaybeAsASCII());
 
     // Set TFLite experiment log path.
     cmd->AppendSwitchASCII(
         tflite_experiment::switches::kTFLiteExperimentLogPath,
-        GetTFLiteExperimentLogPath().value());
+        GetTFLiteExperimentLogPath().MaybeAsASCII());
   }
 
   base::FilePath GetTFLiteExperimentLogPath() {
     base::FilePath g_test_data_directory;
     base::PathService::Get(chrome::DIR_TEST_DATA, &g_test_data_directory);
-    g_test_data_directory =
-        g_test_data_directory.Append(kTFLiteExperimentLogName);
+    g_test_data_directory = g_test_data_directory.Append(
+        FILE_PATH_LITERAL("tflite_experiment.log"));
     return g_test_data_directory;
   }
 

chrome/services/machine_learning/BUILD.gn

@@ -27,6 +27,8 @@ source_set("machine_learning") {
 
   if (build_with_tflite_lib) {
     sources += [
+      "chrome_tflite_op_resolver.cc",
+      "chrome_tflite_op_resolver.h",
       "in_process_tflite_predictor.cc",
       "in_process_tflite_predictor.h",
     ]
@@ -65,6 +67,8 @@ source_set("unit_tests") {
     sources += [ "in_process_tflite_predictor_unittest.cc" ]
   }
 
+  data = [ "//chrome/test/data/" ]
+
   deps = [
     ":machine_learning",
     ":metrics",

chrome/services/machine_learning/chrome_tflite_op_resolver.h

+// Copyright 2021 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_SERVICES_MACHINE_LEARNING_CHROME_TFLITE_OP_RESOLVER_H_
+#define CHROME_SERVICES_MACHINE_LEARNING_CHROME_TFLITE_OP_RESOLVER_H_
+
+#include "third_party/tflite/src/tensorflow/lite/model.h"
+#include "third_party/tflite/src/tensorflow/lite/mutable_op_resolver.h"
+
+namespace machine_learning {
+
+// This class maintains all the currently supported TFLite
+// operations for Chrome and registers them for use.
+class ChromeTFLiteOpResolver : public tflite::MutableOpResolver {
+ public:
+  ChromeTFLiteOpResolver();
+};
+
+}  // namespace machine_learning
+
+#endif  // CHROME_SERVICES_MACHINE_LEARNING_CHROME_TFLITE_OP_RESOLVER_H_

chrome/services/machine_learning/in_process_tflite_predictor.cc

@@ -5,8 +5,8 @@
 #include "chrome/services/machine_learning/in_process_tflite_predictor.h"
 
 #include "base/check.h"
+#include "chrome/services/machine_learning/chrome_tflite_op_resolver.h"
 #include "third_party/tflite/src/tensorflow/lite/interpreter.h"
-#include "third_party/tflite/src/tensorflow/lite/kernels/register.h"
 #include "third_party/tflite/src/tensorflow/lite/model.h"
 
 namespace machine_learning {
@@ -46,7 +46,7 @@ bool InProcessTFLitePredictor::LoadModel() {
 }
 
 bool InProcessTFLitePredictor::BuildInterpreter() {
-  tflite::ops::builtin::BuiltinOpResolver resolver;
+  ChromeTFLiteOpResolver resolver;
   tflite::InterpreterBuilder builder(*model_, resolver);
 
   if (builder(&interpreter_, num_threads_) != kTfLiteOk || !interpreter_)

chrome/services/machine_learning/in_process_tflite_predictor_unittest.cc

@@ -51,7 +51,7 @@ class InProcessTFLitePredictorTest : public ::testing::Test {
                           .Append(FILE_PATH_LITERAL("data"))
                           .Append(FILE_PATH_LITERAL("simple_test.tflite"));
     EXPECT_TRUE(base::PathExists(model_file_path));
-    return model_file_path.value().c_str();
+    return model_file_path.AsUTF8Unsafe();
   }
 };