Modify the getDeviceData api to return no error when the file is missing

Before the API would return an error now it returns no error and an
empty blob instead.

BUG=1046705
TEST=uni_tests

Change-Id: Id15fa397d9db5dcded5db40caac9a719bc9312ee
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2026971Reviewed-by: Owen Min <zmin@chromium.org>
Commit-Queue: Julian Pastarmov <pastarmovj@chromium.org>
Cr-Commit-Position: refs/heads/master@{#736496}

chrome/browser/extensions/api/enterprise_reporting_private/chrome_desktop_report_request_helper.cc

@@ -473,9 +473,16 @@ void RetrieveDeviceData(
     return;
   }
   data_file = data_file.AppendASCII(id);
-  // TODO(pastarmovj): Make sure the resulting path is still a direct file or
-  // subdir+file of the EV folder.
+  // If the file does not exist don't treat this as an error rather return an
+  // empty string.
+  if (!base::PathExists(data_file)) {
+    std::move(callback).Run("", true);
+    return;
+  }
   std::string data;
+  // ReadFileToString does not permit traversal with .. so this is guaranteed to
+  // be a descendant of the data directory up to links created outside of
+  // Chrome.
   bool result = base::ReadFileToString(data_file, &data);
 
   std::move(callback).Run(data, result);

chrome/browser/extensions/api/enterprise_reporting_private/enterprise_reporting_private_unittest.cc

@@ -211,6 +211,32 @@ TEST_F(EnterpriseReportingPrivateDeviceDataFunctionsTest, DeviceDataMissing) {
                                              browser(),
                                              extensions::api_test_utils::NONE);
   ASSERT_TRUE(function->GetResultList());
+  EXPECT_EQ(1u, function->GetResultList()->GetSize());
+  EXPECT_TRUE(function->GetError().empty());
+}
+
+TEST_F(EnterpriseReportingPrivateDeviceDataFunctionsTest, DeviceBadId) {
+  auto set_function =
+      base::MakeRefCounted<EnterpriseReportingPrivateSetDeviceDataFunction>();
+  std::unique_ptr<base::ListValue> set_values =
+      std::make_unique<base::ListValue>();
+  set_values->AppendString("a/b");
+  set_values->Append(
+      std::make_unique<base::Value>(base::Value::BlobStorage({1, 2, 3})));
+  extension_function_test_utils::RunFunction(set_function.get(),
+                                             std::move(set_values), browser(),
+                                             extensions::api_test_utils::NONE);
+  ASSERT_TRUE(set_function->GetError().empty());
+
+  // Try to read the directory as a file and should fail.
+  auto function =
+      base::MakeRefCounted<EnterpriseReportingPrivateGetDeviceDataFunction>();
+  std::unique_ptr<base::ListValue> values = std::make_unique<base::ListValue>();
+  values->AppendString("a");
+  extension_function_test_utils::RunFunction(function.get(), std::move(values),
+                                             browser(),
+                                             extensions::api_test_utils::NONE);
+  ASSERT_TRUE(function->GetResultList());
   EXPECT_EQ(0u, function->GetResultList()->GetSize());
   EXPECT_FALSE(function->GetError().empty());
 }
@@ -263,8 +289,11 @@ TEST_F(EnterpriseReportingPrivateDeviceDataFunctionsTest, RetrieveDeviceData) {
                                              std::move(values2), browser(),
                                              extensions::api_test_utils::NONE);
   ASSERT_TRUE(get_function2->GetResultList());
-  EXPECT_EQ(0u, get_function2->GetResultList()->GetSize());
-  EXPECT_FALSE(get_function2->GetError().empty());
+  EXPECT_TRUE(get_function2->GetResultList()->Get(0, &single_result));
+  EXPECT_TRUE(get_function2->GetError().empty());
+  ASSERT_TRUE(single_result);
+  ASSERT_TRUE(single_result->is_blob());
+  EXPECT_EQ(base::Value::BlobStorage(), single_result->GetBlob());
 }
 
 // TODO(pastarmovj): Remove once implementation for the other platform exists.