Implement Chrome Extension TabCapture API.

chrome/browser/extensions/api/tab_capture/tab_capture_api.h

+// 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.
+
+// Defines the Chrome Extensions Tab Capture API functions for accessing
+// tab media streams.
+
+#ifndef CHROME_BROWSER_EXTENSIONS_API_TAB_CAPTURE_TAB_CAPTURE_API_H_
+#define CHROME_BROWSER_EXTENSIONS_API_TAB_CAPTURE_TAB_CAPTURE_API_H_
+
+#include "chrome/browser/extensions/api/api_function.h"
+#include "chrome/common/extensions/api/experimental_tab_capture.h"
+
+namespace extensions {
+
+class TabCaptureAsyncApiFunction : public AsyncApiFunction {

[Aaron Boodman, 2012/10/04 07:21:43]

Is it possible to use IOThreadExtensionFunction instead? It is more efficient as
it avoid a round-trip from the UI thread. Also I'm not sure that
AsyncApiFunction should exist, so I'd rather not add dependencies.

[justinlin, 2012/10/08 09:58:31]

I can't seem to return a value when I use that interface. It crashes here:
https://cs.corp.google.com/#chrome/src/chrome/browser/extensions/extension_fu...

AsyncApiFunction seems like what I want though.

[Aaron Boodman, 2012/10/16 04:19:27]

ExtensionFunctionDispatcher is handling this function for some reason, but it
can only handle UI thread functions. The IO thread functions are supposed to be
handled differently (see ExtensionFunctionDispatcher::DispatchOnIOThread).

I can't remember what causes one path or the other to be taken. You can take a
look at some other classes that inherit IOThreadExtensionFunction do and see if
you can do that as well?

[Aaron Boodman, 2012/10/16 04:22:28]

Note: This comment only applies if
http://codereview.chromium.org/11038021/diff/36001/chrome/browser/extensions/...
is wrong for some reason.

[justinlin, 2012/10/17 08:32:26]

OK, so from what I can tell, this would make the function entirely on the IO
thread (is this correct?). I need to be on the IO thread to figure out the
process and routing id, but then the UI thread to add it to the registry. I
could use ExtensionUI/IOFunction and post a task, but I think it ends up being
the same as AsyncApiFunction. That class is also used for pretty fundamental
things like the socket/usb/etc api's. If those migrate, it should be easy to
change this class too. If you don't think so, I'll take a closer look.

+ public:
+  TabCaptureAsyncApiFunction();
+
+ protected:
+  virtual ~TabCaptureAsyncApiFunction();
+
+  // AsyncApiFunction:
+  virtual bool Respond() OVERRIDE;
+};
+
+class TabCaptureGetTabMediaFunction : public TabCaptureAsyncApiFunction {
+ public:
+  DECLARE_EXTENSION_FUNCTION_NAME("experimental.tabCapture.getTabMedia");
+  TabCaptureGetTabMediaFunction();
+
+ protected:
+  virtual ~TabCaptureGetTabMediaFunction();
+
+  // AsyncApiFunction:
+  virtual bool Prepare() OVERRIDE;
+  virtual void Work() OVERRIDE;
+
+ private:
+  scoped_ptr<api::experimental_tab_capture::GetTabMedia::Params> params_;
+};
+
+class TabCaptureGetCapturedTabsFunction : public TabCaptureAsyncApiFunction {
+ public:
+  DECLARE_EXTENSION_FUNCTION_NAME("experimental.tabCapture.getCapturedTabs");
+  TabCaptureGetCapturedTabsFunction();
+
+ protected:
+  virtual ~TabCaptureGetCapturedTabsFunction();
+
+  // AsyncApiFunction:
+  virtual bool Prepare() OVERRIDE;
+  virtual void Work() OVERRIDE;
+
+ private:
+};
+
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_API_TAB_CAPTURE_TAB_CAPTURE_API_H_