Move c/b/extension/api/* into extensions namespace

chrome/browser/extensions/api/webview/webview_api.h

 // Copyright (c) 2013 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 CHROME_BROWSER_EXTENSIONS_API_WEBVIEW_WEBVIEW_API_H_
 #define CHROME_BROWSER_EXTENSIONS_API_WEBVIEW_WEBVIEW_API_H_
 
 #include "chrome/browser/extensions/api/execute_code_function.h"
 
+namespace extensions {
+
 class WebviewClearDataFunction : public AsyncExtensionFunction {
  public:
   DECLARE_EXTENSION_FUNCTION("webview.clearData", WEBVIEW_CLEARDATA);
 
   WebviewClearDataFunction();
 
  protected:
   virtual ~WebviewClearDataFunction();
 
   // ExtensionFunction implementation.
@@ skipping 143 matching lines @@
  protected:
   virtual ~WebviewTerminateFunction();
 
   // ExtensionFunction implementation.
   virtual bool RunImpl() OVERRIDE;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(WebviewTerminateFunction);
 };
 
+}  // namespace extensions
+
 #endif  // CHROME_BROWSER_EXTENSIONS_API_WEBVIEW_WEBVIEW_API_H_