[headless] Initial skeleton of headless/public/

headless/public/web_frame.h

+// 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.
+
+#ifndef HEADLESS_PUBLIC_WEB_FRAME_H_
+#define HEADLESS_PUBLIC_WEB_FRAME_H_
+
+#include "base/callback.h"
+#include "base/values.h"
+#include "headless/public/headless_export.h"
+
+namespace headless {
+
+class WebDocument;
+
+class HEADLESS_EXPORT WebFrame {

[Sami, 2015/12/01 14:03:58]

nit: Add a description and say that this also belongs to the renderer main
thread.

[altimin, 2015/12/01 15:17:29]

Done.

+ public:
+  virtual ~WebFrame() {}
+
+  using ScriptExecutionCallback =
+      base::Callback<void(const std::vector<scoped_ptr<base::Value>>&)>;
+
+  // Schedule given script for execution.

[Sami, 2015/12/01 14:03:58]

Maybe: Execute the given script, ignoring its return value.

Assuming we can remove the callback below, maybe we should drop this function
completely and always return the value?

[altimin, 2015/12/01 15:17:29]

There are two different methods in underlying Blink API.
Looks like that the version without returning value is more efficient.

+  virtual void ExecuteScript(const std::string& source_code) = 0;
+
+  // Execute given script and return value.

[Sami, 2015/12/01 14:03:58]

s/value/its result/.

[altimin, 2015/12/01 15:17:29]

Done.

+  // Returned value will be converted to json (base::Value).
+  // Special effects to bear in mind:
+  // - Boolean will be converted to base::FundamentalValue (no surprises here).
+  // - Number will be converted to base::FundamentalValue.
+  // - Array will be converted to base::ListValue.
+  //   Note: All non-numerical properties will be omitted
+  //   (e.g. "array = [1, 2, 3]; array['property'] = 'value'; return array"
+  //    will return [1, 2, 3]).
+  // - Object will be converted to base::DictionaryValue
+  //   Note: Only string can be key in base::DictionaryValue, so all non-string
+  //   properties will be omitted
+  //   (e.g. "obj = Object(); obj['key'] = 'value'; obj[0] = 42;" will return
+  //    {"key":"value"}).
+  virtual void ExecuteScriptAndReturnValue(

[Sami, 2015/12/01 14:03:58]

Since this is all running on the renderer main thread, I think we can just
return the result directly without a callback.

[altimin, 2015/12/01 15:17:29]

No, we can't. Underlying API returns a callback so we are stuck with callbacks.

[Sami, 2015/12/01 17:47:33]

Are you sure? This one looks synchronous:

https://code.google.com/p/chromium/codesearch#chromium/src/third_party/WebKit...

[altimin, 2015/12/01 18:42:46]

But it is deprecated and async version should be used. 

[Sami, 2015/12/01 18:53:53]

Ah, I missed that. This is fine then.

+      const std::string& source_code,
+      const ScriptExecutionCallback& callback) = 0;
+};
+
+}  // namespace headless
+
+#endif  // HEADLESS_PUBLIC_WEB_FRAME_H_