Add Click to Open PDF Placeholder feature

chrome/common/chrome_features.h

 // Copyright 2016 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.
 
 // This file defines all the public base::FeatureList features for the chrome
 // module.
 
 #ifndef CHROME_COMMON_CHROME_FEATURES_H_
 #define CHROME_COMMON_CHROME_FEATURES_H_
 
@@ skipping 44 matching lines @@
 extern const base::Feature kBrowserTouchBar;
 extern const base::Feature kTabStripKeyboardFocus;
 #endif  // defined(OS_MACOSX)
 
 extern const base::Feature kCaptureThumbnailDependingOnTransitionType;
 
 extern const base::Feature kCaptureThumbnailOnLoadFinished;
 
 extern const base::Feature kCheckInstallabilityForBannerOnLoad;
 
+extern const base::Feature kClickToOpenPDFPlaceholder;
+
 #if defined(OS_ANDROID)
 extern const base::Feature kConsistentOmniboxGeolocation;
 #endif
 
 #if defined(OS_ANDROID)
 extern const base::Feature kCopylessPaste;
 #endif
 
 #if defined(OS_WIN)
 extern const base::Feature kDesktopIOSPromotion;
@@ skipping 130 matching lines @@
 #endif  // defined(OS_CHROMEOS)
 
 bool PrefServiceEnabled();
 
 // DON'T ADD RANDOM STUFF HERE. Put it in the main section above in
 // alphabetical order, or in one of the ifdefs (also in order in each section).
 
 }  // namespace features
 
 #endif  // CHROME_COMMON_CHROME_FEATURES_H_