Prefer opening PDF downloads in the browser.

chrome/browser/download/download_target_determiner_delegate.h

 // Copyright 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_DOWNLOAD_DOWNLOAD_TARGET_DETERMINER_DELEGATE_H_
 #define CHROME_BROWSER_DOWNLOAD_DOWNLOAD_TARGET_DETERMINER_DELEGATE_H_
 
 #include "base/callback_forward.h"
 
 #include "chrome/browser/download/download_path_reservation_tracker.h"
@@ skipping 44 matching lines @@
   // |virtual_path| is already a local path, then |virtual_path| should be
   // returned as-is.
   typedef base::Callback<void(const base::FilePath&)> LocalPathCallback;
 
   // Callback to be invoked after CheckDownloadUrl() completes. The parameter to
   // the callback should indicate the danger type of the download based on the
   // results of the URL check.
   typedef base::Callback<void(content::DownloadDangerType danger_type)>
   CheckDownloadUrlCallback;
 
+  // Callback to be invoked after GetFileMimeType() completes. The parameter
+  // should be the MIME type of the requested file. If no MIME type can be
+  // determined, it should be set to the empty string.
+  typedef base::Callback<void(const std::string&)> GetFileMimeTypeCallback;
+
   // Notifies extensions of the impending filename determination. |virtual_path|
   // is the current suggested virtual path. The |callback| should be invoked to
   // indicate whether any extensions wish to override the path.
   virtual void NotifyExtensions(content::DownloadItem* download,
                                 const base::FilePath& virtual_path,
                                 const NotifyExtensionsCallback& callback) = 0;
 
   // Reserve |virtual_path|. This is expected to check the following:
   // - Whether |virtual_path| can be written to by the user. If not, the
   //   |virtual_path| can be changed to writeable path if necessary.
@@ skipping 28 matching lines @@
   virtual void DetermineLocalPath(content::DownloadItem* download,
                                   const base::FilePath& virtual_path,
                                   const LocalPathCallback& callback) = 0;
 
   // Check whether the download URL is malicious and invoke |callback| with a
   // suggested danger type for the download.
   virtual void CheckDownloadUrl(content::DownloadItem* download,
                                 const base::FilePath& virtual_path,
                                 const CheckDownloadUrlCallback& callback) = 0;
 
+  // Get the MIME type for the given file.
+  virtual void GetFileMimeType(const base::FilePath& path,
+                               const GetFileMimeTypeCallback& callback) = 0;
  protected:
   virtual ~DownloadTargetDeterminerDelegate();
 };
 
 #endif  // CHROME_BROWSER_DOWNLOAD_DOWNLOAD_TARGET_DETERMINER_DELEGATE_H_