Unset the page-scale-factor limits if enable-pinch flag is turned on.

content/browser/web_contents/web_contents_impl.cc

 // Copyright (c) 2012 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.
 
 #include "content/browser/web_contents/web_contents_impl.h"
 
 #include <utility>
 
 #include "base/command_line.h"
 #include "base/metrics/histogram.h"
@@ skipping 532 matching lines @@
   if (rvh->GetView()) {
     gfx::Monitor monitor = gfx::Screen::GetMonitorNearestWindow(
         rvh->GetView()->GetNativeView());
     prefs.default_device_scale_factor =
         static_cast<int>(monitor.device_scale_factor());
   } else {
     prefs.default_device_scale_factor =
         gfx::Monitor::GetDefaultDeviceScaleFactor();;
   }
 #endif
+  prefs.force_enable_page_scale =
+      command_line.HasSwitch(switches::kEnablePinch);
 
   if (command_line.HasSwitch(switches::kDefaultTileWidth))
     prefs.default_tile_width =
         GetSwitchValueAsInt(command_line, switches::kDefaultTileWidth, 1);
   if (command_line.HasSwitch(switches::kDefaultTileHeight))
     prefs.default_tile_height =
         GetSwitchValueAsInt(command_line, switches::kDefaultTileHeight, 1);
   if (command_line.HasSwitch(switches::kMaxUntiledLayerWidth))
     prefs.max_untiled_layer_width =
         GetSwitchValueAsInt(command_line, switches::kMaxUntiledLayerWidth, 1);
@@ skipping 2474 matching lines @@
 void WebContentsImpl::CreateViewAndSetSizeForRVH(RenderViewHost* rvh) {
   RenderWidgetHostView* rwh_view = GetView()->CreateViewForWidget(rvh);
   // Can be NULL during tests.
   if (rwh_view)
     rwh_view->SetSize(GetView()->GetContainerSize());
 }
 
 RenderViewHostImpl* WebContentsImpl::GetRenderViewHostImpl() {
   return static_cast<RenderViewHostImpl*>(GetRenderViewHost());
 }