Cache feedback reports to disk in case of send failure.

chrome/browser/feedback/feedback_report.cc

+// Copyright 2014 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.
+
+#include "chrome/browser/feedback/feedback_report.h"
+
+#include "base/file_util.h"
+#include "base/files/file_enumerator.h"
+#include "base/files/important_file_writer.h"
+#include "base/guid.h"
+#include "base/strings/string_number_conversions.h"
+#include "content/public/browser/browser_context.h"
+#include "content/public/browser/browser_thread.h"
+#include "net/base/directory_lister.h"
+
+using content::BrowserThread;
+
+namespace {
+
+const base::FilePath::CharType kFeedbackReportPath[] =
+    FILE_PATH_LITERAL("Feedback Reports");
+const base::FilePath::CharType kFeedbackReportFilenameWildcard[] =
+    FILE_PATH_LITERAL("Feedback Report.*");
+
+const char kFeedbackReportFilenamePrefix[] = "Feedback Report.";
+
+base::FilePath GetFeedbackReportsPath(content::BrowserContext* context) {
+  return context->GetPath().Append(kFeedbackReportPath);
+}
+
+// We need this function to post a task to delete file (which returns a bool

[Lei Zhang, 2014/01/23 22:28:41]

I think the correct way to do this is with base::IgnoreResult()

[rkc, 2014/01/23 22:57:21]

Ah, I knew there had to be a better way to do this. Thanks!
Done.

+// causing Bind to fail compile).
+void DeleteFileNoReturn(base::FilePath file, bool recursive) {
+  base::DeleteFile(file, recursive);
+}
+
+}  // namespace
+
+namespace feedback {
+
+FeedbackReport::FeedbackReport(
+    content::BrowserContext* context,

[Lei Zhang, 2014/01/23 22:28:41]

nit: this fits on the previous line; align the other parameters with this one; 4
space indent the initializer list on its own line.

[rkc, 2014/01/23 22:57:21]

Done.

+    const base::Time& upload_at,
+    const std::string& data) : context_(context),
+                               upload_at_(upload_at),
+                               data_(data) {
+  base::FilePath reports_path = GetFeedbackReportsPath(context);
+  if (reports_path.empty())
+    return;
+  file_ = reports_path.AppendASCII(
+      kFeedbackReportFilenamePrefix + base::GenerateGUID());
+  content::BrowserThread::PostBlockingPoolTask(

[Lei Zhang, 2014/01/23 22:28:41]

since you already declared "using content::BrowserThread", you can omit
content:: here and below.

[rkc, 2014/01/23 22:57:21]

Done.

+      FROM_HERE, base::Bind(
+          &FeedbackReport::WriteReportOnBlockingPool, this));
+}
+
+FeedbackReport::~FeedbackReport() {}
+
+void FeedbackReport::DeleteReportOnDisk() {
+  content::BrowserThread::PostBlockingPoolTask(
+      FROM_HERE, base::Bind(
+          &DeleteFileNoReturn, file_, false));
+  file_.clear();
+}
+
+void FeedbackReport::WriteReportOnBlockingPool() {
+  base::FilePath reports_path = GetFeedbackReportsPath(context_);
+  if (!base::DirectoryExists(reports_path)) {
+    base::File::Error error;
+    if (!base::CreateDirectoryAndGetError(reports_path, &error))
+      return;
+  }
+  if (!file_.empty())
+    base::ImportantFileWriter::WriteFileAtomically(file_, data_);
+}
+
+// static
+void FeedbackReport::LoadReportsAndQueue(
+    content::BrowserContext* context, QueueCallback callback) {
+  base::FilePath reports_path = GetFeedbackReportsPath(context);
+  if (reports_path.empty())
+    return;
+
+  base::FileEnumerator enumerator(reports_path,
+                                  false,
+                                  base::FileEnumerator::FILES,
+                                  kFeedbackReportFilenameWildcard);
+  for (base::FilePath name = enumerator.Next();
+       !name.empty();
+       name = enumerator.Next()) {
+    std::string data;
+    if (ReadFileToString(name, &data)) {
+      content::BrowserThread::PostTask(
+          BrowserThread::UI,
+          FROM_HERE,
+          base::Bind(callback, data));
+    }
+    base::DeleteFile(name, false);
+  }
+}
+
+}  // namespace feedback