[Android WebView] Add DevTools Timeline instrumentation for embedder callbacks

This allows displaying time spent in WebView callbacks code, which can
affect loading and page displaying times.

BUG=344871

Review URL: https://codereview.chromium.org/171793006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252919 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 39 insertions, 0 deletions

diff --git a/android_webview/common/devtools_instrumentation.h b/android_webview/common/devtools_instrumentation.h
new file mode 100644
index 0000000..822ffc1
--- /dev/null
+++ b/android_webview/common/devtools_instrumentation.h
@@ -0,0 +1,39 @@
+// 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.
+
+#ifndef ANDROID_WEBVIEW_COMMON_DEVTOOLS_INSTRUMENTATION_H_
+#define ANDROID_WEBVIEW_COMMON_DEVTOOLS_INSTRUMENTATION_H_
+
+#include "base/debug/trace_event.h"
+
+namespace android_webview {
+namespace devtools_instrumentation {
+
+namespace internal {
+const char kCategory[] = "Java,devtools";
+const char kEmbedderCallback[] = "EmbedderCallback";
+const char kCallbackNameArgument[] = "callbackName";
+}  // namespace internal
+
+class ScopedEmbedderCallbackTask {
+ public:
+  ScopedEmbedderCallbackTask(const char* callback_name) {
+    TRACE_EVENT_BEGIN1(internal::kCategory,
+                       internal::kEmbedderCallback,
+                       internal::kCallbackNameArgument,
+                       callback_name);
+  }
+  ~ScopedEmbedderCallbackTask() {
+    TRACE_EVENT_END0(internal::kCategory,
+                     internal::kEmbedderCallback);
+  }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ScopedEmbedderCallbackTask);
+};
+
+}  // namespace devtools_instrumentation
+}  // namespace android_webview
+
+#endif  // ANDROID_WEBVIEW_COMMON_DEVTOOLS_INSTRUMENTATION_H_