More aggressive IO asserts in content_browsertests.

content/browser/accessibility/dump_accessibility_browsertest_base.cc

Index: content/browser/accessibility/dump_accessibility_browsertest_base.cc
diff --git a/content/browser/accessibility/dump_accessibility_browsertest_base.cc b/content/browser/accessibility/dump_accessibility_browsertest_base.cc
index d4eab1b38746818e00f16e94c15a856aae22eb8f..af1e10e1d7863fb022ca4133e63638c851e9d739 100644
--- a/content/browser/accessibility/dump_accessibility_browsertest_base.cc
+++ b/content/browser/accessibility/dump_accessibility_browsertest_base.cc
@@ -15,6 +15,7 @@
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/threading/thread_restrictions.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "build/build_config.h"
 #include "content/browser/accessibility/accessibility_tree_formatter.h"
@@ -204,24 +205,30 @@ void DumpAccessibilityTestBase::RunTestForPlatform(
                 : " (native accessibility tree for this platform)");
 
   std::string html_contents;
-  base::ReadFileToString(file_path, &html_contents);
-
-  // Read the expected file.
+  base::FilePath expected_file;
   std::string expected_contents_raw;
-  base::FilePath expected_file =
-      base::FilePath(file_path.RemoveExtension().value() +
-                     formatter_->GetExpectedFileSuffix());
-  if (!base::PathExists(expected_file)) {
-    LOG(INFO) << "File not found: " << expected_file.LossyDisplayName();
-    LOG(INFO) << "No expectation file present, ignoring test on this platform."
-              << " To run this test anyway, create "
-              << expected_file.LossyDisplayName()
-              << " (it can be empty) and then run content_browsertests "
-              << "with the switch: --"
-              << switches::kGenerateAccessibilityTestExpectations;
-    return;
+  {
+    base::ThreadRestrictions::ScopedAllowIO allow_io_for_test_setup;
+    base::ReadFileToString(file_path, &html_contents);
+
+    // Read the expected file.
+    expected_file =
+        base::FilePath(file_path.RemoveExtension().value() +
+                       formatter_->GetExpectedFileSuffix());
+
+    if (!base::PathExists(expected_file)) {
+      LOG(INFO) << "File not found: " << expected_file.LossyDisplayName();
+      LOG(INFO)
+          << "No expectation file present, ignoring test on this platform."
+          << " To run this test anyway, create "
+          << expected_file.LossyDisplayName()
+          << " (it can be empty) and then run content_browsertests "
+          << "with the switch: --"
+          << switches::kGenerateAccessibilityTestExpectations;
+      return;
+    }
+    base::ReadFileToString(expected_file, &expected_contents_raw);
   }
-  base::ReadFileToString(expected_file, &expected_contents_raw);
 
   // Tolerate Windows-style line endings (\r\n) in the expected file:
   // normalize by deleting all \r from the file (if any) to leave only \n.
@@ -380,6 +387,7 @@ void DumpAccessibilityTestBase::RunTestForPlatform(
 
     if (base::CommandLine::ForCurrentProcess()->HasSwitch(
             switches::kGenerateAccessibilityTestExpectations)) {
+      base::ThreadRestrictions::ScopedAllowIO allow_io_to_write_expected_file;
       CHECK(base::WriteFile(
           expected_file, actual_contents.c_str(), actual_contents.size()));
       LOG(INFO) << "Wrote expectations to: "