plumbing for skia trace events into Chrome's about://tracing framework

skia/ext/trace_event.h

Index: skia/ext/trace_event.h
diff --git a/skia/ext/trace_event.h b/skia/ext/trace_event.h
new file mode 100644
index 0000000000000000000000000000000000000000..b93c0ca919e29ce647577b6e85e9d38d3b94260f
--- /dev/null
+++ b/skia/ext/trace_event.h
@@ -0,0 +1,34 @@
+// Copyright (c) 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 SKIA_EXT_TRACE_EVENT_H_

[nduca, 2014/02/04 01:15:19]

unless skia/ folder has its own subclassing conventions, i'd suggest

skia/ext/event_tracer_impl.h

with just a single global function, InitSkiaEventTracer or something similarly
named. Nobody in the chrome side of things is intended to see this subclass, you
see, so you can declare the subclass in event_tracer_impl.cc and register it
right there.

[humper, 2014/02/04 19:58:08]

Done.

+#define SKIA_EXT_TRACE_EVENT_H_
+
+#include "third_party/skia/include/utils/SkEventTracer.h"
+
+namespace skia {
+
+class SkChromiumEventTracer: public SkEventTracer {
+  virtual const uint8_t* getCategoryGroupEnabled(const char* name);
+  virtual const char* getCategoryGroupName(
+      const uint8_t* categoryEnabledFlag);
+  virtual SkEventTracer::Handle
+    addTraceEvent(char phase,
+                  const uint8_t* categoryEnabledFlag,
+                  const char* name,
+                  uint64_t id,
+                  int32_t numArgs,
+                  const char** argNames,
+                  const uint8_t* argTypes,
+                  const uint64_t* argValues,
+                  uint8_t flags);
+  virtual void
+    updateTraceEventDuration(const uint8_t* categoryEnabledFlag,
+                             const char *name,
+                             SkEventTracer::Handle handle);
+};
+
+} // namespace skia
+
+#endif  // SKIA_EXT_TRACE_EVENT_H_