Fix tests and enable virtual viewport on Android WebView.

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 b7ef1947544b7af0fd8a6859d2bcb7f274e1319e..1bf3c5de24fa8ee4bb386bdee6e5d1ec73c67393 100644
--- a/android_webview/lib/main/aw_main_delegate.cc
+++ b/android_webview/lib/main/aw_main_delegate.cc
@@ -79,9 +79,6 @@ bool AwMainDelegate::BasicStartupComplete(int* exit_code) {
   // 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;
 }