Enable Tracing on content shell for Android

content/shell/android/tracing_shell.h

Index: content/shell/android/tracing_shell.h
diff --git a/content/shell/android/tracing_shell.h b/content/shell/android/tracing_shell.h
new file mode 100644
index 0000000000000000000000000000000000000000..44e40e2544e0ae6c232b03eda194e1c7d97ef1f1
--- /dev/null
+++ b/content/shell/android/tracing_shell.h
@@ -0,0 +1,53 @@
+// Copyright (c) 2012 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  CONTENT_SHELL_ANDROID_TRACING_SHELL_H
+#define  CONTENT_SHELL_ANDROID_TRACING_SHELL_H
+
+#include <jni.h>
+#include <string>
+
+#include "base/file_util.h"
+#include "content/public/browser/trace_subscriber.h"
+
+namespace content {
+
+// Registers the TraceController native methods.
+bool RegisterTracingHandler(JNIEnv* env);

[Ted C, 2012/12/26 16:18:28]

this should be RegisterTracingIntentHandler

+
+class TracingIntentHandler

[Ted C, 2012/12/26 16:18:28]

the file name and ifdef should match this class name.

+    :  public content::TraceSubscriber {

[Ted C, 2012/12/26 16:18:28]

I think it would be better to just extend from TraceSubscriberStdio to avoid
having to handle the formatting yourself.  That would require this to move to
content/browser/android and content/public/android/java, but that would allow us
to share this implementation with TestShell as well (and hopefully Chrome on
Android too).

+ public:
+  TracingIntentHandler();
+  virtual ~TracingIntentHandler() {}
+
+  // TraceSubscriber

[Ted C, 2012/12/26 16:18:28]

Add "implementation" to the end so it's clearer.

+  virtual void OnEndTracingComplete();
+  virtual void OnTraceDataCollected(
+      const scoped_refptr<base::RefCountedString>& trace_fragment);
+
+  // IntentHandler
+  void OnBeginTracing(std::string path);
+  void OnEndTracing();
+
+  bool in_tracing() { return in_tracing_; }
+  void SetInTracing(bool tracing) { in_tracing_ = tracing; }

[Ted C, 2012/12/26 16:18:28]

if you are inlining functions in the header, it should be named in hacker style.

set_in_tracing(bool tracing) {...}

http://dev.chromium.org/developers/coding-style#TOC-Inline-functions

+
+  struct JsonString {

[Ted C, 2012/12/26 16:18:28]

This should probably be a class as well since it's not just a simple data
object.

+    void Start();
+    void AddFragment(const std::string&);
+    void Finish();
+
+    bool first_;
+    std::string data_;
+  };
+
+ private:
+  bool in_tracing_;
+  FilePath path_to_save_;
+  JsonString trace_data_to_save_;
+};
+
+}  // namespace content
+#endif  // CONTENT_SHELL_ANDROID_TRACING_SHELL_H