Add granular file tracing.

content/browser/tracing/file_tracing_provider_impl.cc

+// Copyright 2015 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 "content/browser/tracing/file_tracing_provider_impl.h"
+
+#include "base/files/file_path.h"
+#include "base/trace_event/trace_event.h"
+
+namespace content {
+
+const char kFileTracingEventCategoryGroup[] = TRACE_DISABLED_BY_DEFAULT("file");
+
+FileTracingProviderImpl::FileTracingProviderImpl() {}
+FileTracingProviderImpl::~FileTracingProviderImpl() {}
+
+bool FileTracingProviderImpl::FileTracingCategoryIsEnabled() const {
+  bool enabled;
+  TRACE_EVENT_CATEGORY_GROUP_ENABLED(kFileTracingEventCategoryGroup, &enabled);
+  return enabled;
+}
+
+void FileTracingProviderImpl::FileTracingEnable(void* id) {
+  TRACE_EVENT_NESTABLE_ASYNC_BEGIN0(
+      kFileTracingEventCategoryGroup, FILE_TRACING_PREFIX, id);
+}
+
+void FileTracingProviderImpl::FileTracingDisable(void* id) {
+  TRACE_EVENT_NESTABLE_ASYNC_END0(
+      kFileTracingEventCategoryGroup, FILE_TRACING_PREFIX, id);
+}
+
+void FileTracingProviderImpl::FileTracingEventBegin(
+    const char* name, void* id, const base::FilePath& path, int64 size) {
+  if (size) {
+    TRACE_EVENT_NESTABLE_ASYNC_BEGIN2(kFileTracingEventCategoryGroup, name, id,
+        "path", path.AsUTF8Unsafe(), "size", size);
+  } else {
+    TRACE_EVENT_NESTABLE_ASYNC_BEGIN1(kFileTracingEventCategoryGroup, name, id,
+        "path", path.AsUTF8Unsafe());
+  }
+}
+
+void FileTracingProviderImpl::FileTracingEventEnd(
+    const char* name, void* id, const base::FilePath& path, int64 size) {
+  if (size) {
+    TRACE_EVENT_NESTABLE_ASYNC_END2(kFileTracingEventCategoryGroup, name, id,
+        "path", path.AsUTF8Unsafe(), "size", size);
+  } else {
+    TRACE_EVENT_NESTABLE_ASYNC_END1(kFileTracingEventCategoryGroup, name, id,
+        "path", path.AsUTF8Unsafe());
+  }
+}
+
+}  // namespace content