Ignore viewport meta tags when Request Desktop Site is enabled.

content/browser/renderer_host/render_view_host_impl.cc

Index: content/browser/renderer_host/render_view_host_impl.cc
diff --git a/content/browser/renderer_host/render_view_host_impl.cc b/content/browser/renderer_host/render_view_host_impl.cc
index 4a8e86b36ef797495dfc657c799570b1bfd82d86..74dc94b2e48b19cb89a73df89f589dd83c188e81 100644
--- a/content/browser/renderer_host/render_view_host_impl.cc
+++ b/content/browser/renderer_host/render_view_host_impl.cc
@@ -493,9 +493,10 @@ WebPreferences RenderViewHostImpl::ComputeWebkitPrefs() {
 
   prefs.number_of_cpu_cores = base::SysInfo::NumberOfProcessors();
 
-  prefs.viewport_enabled =
-      command_line.HasSwitch(switches::kEnableViewport) ||
-      prefs.viewport_meta_enabled;
+  prefs.viewport_enabled = command_line.HasSwitch(switches::kEnableViewport);
+
+  if (delegate_ && delegate_->IsOverridingUserAgent())
+    prefs.viewport_meta_enabled = false;
 
   prefs.main_frame_resizes_are_orientation_changes =
       command_line.HasSwitch(switches::kMainFrameResizesAreOrientationChanges);