Browser-wide audio mirroring for TabCapture API

content/browser/renderer_host/media/web_contents_capture_util.cc

 // 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.
 
 #include "content/browser/renderer_host/media/web_contents_capture_util.h"
 
 #include "base/string_number_conversions.h"
 #include "base/string_piece.h"
+#include "base/string_util.h"
+
+namespace {
+
+const char kVirtualDeviceScheme[] = "virtual://";
+
+}  // namespace
 
 namespace content {
 
+std::string WebContentsCaptureUtil::AppendWebContentsDeviceScheme(
+    const std::string& device_id) {
+  return kVirtualDeviceScheme + device_id;
+}
+
+bool WebContentsCaptureUtil::IsWebContentsDeviceId(
+    const std::string& device_id) {
+  return StartsWithASCII(device_id, kVirtualDeviceScheme, true);
+}
+
 bool WebContentsCaptureUtil::ExtractTabCaptureTarget(
-    const std::string& device_id,
+    const std::string& device_id_param,
     int& render_process_id,
     int& render_view_id) {
+  DCHECK(IsWebContentsDeviceId(device_id_param));
+  const std::string device_id = device_id_param.substr(
+      strlen(kVirtualDeviceScheme), device_id_param.length());

[miu, 2012/11/21 07:29:49]

nit: strlen() must compute the length every time.  Use
ARRAYSIZE(kVirtualDeviceScheme) - 1 instead.

[justinlin, 2012/11/21 08:09:54]

Done. Nice catch.

+
   const size_t sep_pos = device_id.find(':');
   if (sep_pos == std::string::npos)
     return false;
 
   const base::StringPiece component1(device_id.data(), sep_pos);
   const base::StringPiece component2(device_id.data() + sep_pos + 1,
                                      device_id.length() - sep_pos - 1);
 
   return (base::StringToInt(component1, &render_process_id) &&
           base::StringToInt(component2, &render_view_id));
 }
 
 }  // namespace content