Chromium compositor change implementing page-scale driven pinch-zoom.

content/renderer/render_view_impl.cc

Index: content/renderer/render_view_impl.cc
===================================================================
--- content/renderer/render_view_impl.cc	(revision 157978)
+++ content/renderer/render_view_impl.cc	(working copy)
@@ -3084,6 +3084,8 @@
       command_line.HasSwitch(switches::kEnableFixedLayout);
   bool enable_pinch = enable_viewport ||
                       command_line.HasSwitch(switches::kEnablePinch);
+  bool enable_pinch_in_compositor =
+      command_line.HasSwitch(switches::kEnablePinchInCompositor);
 
   webview()->enableFixedLayoutMode(enable_fixed_layout || enable_viewport);
   webview()->settings()->setFixedElementsLayoutRelativeToFrame(true);
@@ -3096,6 +3098,11 @@
     webview()->setPageScaleFactorLimits(1, 1);
   }
 
+  if (enable_pinch_in_compositor &&
+      webview()->isAcceleratedCompositingActive()) {
+    webview()->setPageScaleFactorLimits(1, 4);
+  }
+
   if (enable_viewport) {
     webview()->settings()->setViewportEnabled(true);
   } else if (enable_fixed_layout) {