Revert of Enable virtual viewport on all platforms

android_webview/lib/main/aw_main_delegate.cc

Index: android_webview/lib/main/aw_main_delegate.cc
diff --git a/android_webview/lib/main/aw_main_delegate.cc b/android_webview/lib/main/aw_main_delegate.cc
index 1db014d7731b99e832c981106f536ee29fcfbfcc..deb5fee4b48fab24ee74e2727626a0778350cf31 100644
--- a/android_webview/lib/main/aw_main_delegate.cc
+++ b/android_webview/lib/main/aw_main_delegate.cc
@@ -20,7 +20,6 @@
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/threading/thread_restrictions.h"
-#include "cc/base/switches.h"
 #include "content/browser/media/android/browser_media_player_manager.h"
 #include "content/public/browser/browser_main_runner.h"
 #include "content/public/browser/browser_thread.h"
@@ -84,10 +83,6 @@
 
   // This is needed for sharing textures across the different GL threads.
   cl->AppendSwitch(switches::kEnableThreadedTextureMailboxes);
-
-  // Virtual viewport doesn't behave well with web view. crbug.com/426891
-  cl->AppendSwitch(cc::switches::kDisablePinchVirtualViewport);
-
   return false;
 }