Enable pinch-to-zoom on Windows 8 by default

content/browser/frame_host/render_widget_host_view_guest.cc

Index: content/browser/frame_host/render_widget_host_view_guest.cc
diff --git a/content/browser/frame_host/render_widget_host_view_guest.cc b/content/browser/frame_host/render_widget_host_view_guest.cc
index ee03e694f6e11ef30bb6909563a6fb806b105692..9ee16e184dbb50d607854ce5da46714b78a45db2 100644
--- a/content/browser/frame_host/render_widget_host_view_guest.cc
+++ b/content/browser/frame_host/render_widget_host_view_guest.cc
@@ -22,6 +22,10 @@
 #import "content/browser/renderer_host/render_widget_host_view_mac_dictionary_helper.h"
 #endif
 
+#if defined(OS_WIN)
+#include "base/win/windows_version.h"
+#endif
+
 #if defined(OS_WIN) || defined(USE_AURA)
 #include "content/browser/renderer_host/ui_events_helper.h"
 #endif
@@ -32,7 +36,12 @@ namespace {
 
 #if defined(OS_WIN) || defined(USE_AURA)
 bool ShouldSendPinchGesture() {
+#if defined(OS_WIN)
+  if (base::win::GetVersion() >= base::win::VERSION_WIN8)
+    return true;
+#endif
   static bool pinch_allowed =
+      CommandLine::ForCurrentProcess()->HasSwitch(switches::kEnableViewport) ||
       CommandLine::ForCurrentProcess()->HasSwitch(switches::kEnablePinch);
   return pinch_allowed;
 }