Allow zoom-in as alternative to popup when tapping multiple targets.

content/public/common/renderer_preferences.h

Index: content/public/common/renderer_preferences.h
diff --git a/content/public/common/renderer_preferences.h b/content/public/common/renderer_preferences.h
index 7735ca3d3277fdb93d2e4f5ab9fc469ba0ac692c..941d10ba5dd90c5126692c0689e861d0a2b707ab 100644
--- a/content/public/common/renderer_preferences.h
+++ b/content/public/common/renderer_preferences.h
@@ -37,6 +37,11 @@ enum RendererPreferencesSubpixelRenderingEnum {
   RENDERER_PREFERENCES_SUBPIXEL_RENDERING_VBGR,
 };
 
+enum DidTapMultipleTargetsStrategy {
+  MULTITARGET_ZOOM = 0,
+  MULTITARGET_POPUP,
+};
+
 struct CONTENT_EXPORT RendererPreferences {
   RendererPreferences();
   ~RendererPreferences();
@@ -126,6 +131,9 @@ struct CONTENT_EXPORT RendererPreferences {
 
   // Controls deacceleration of touchscreen-initiated flings.
   std::vector<float> touchscreen_fling_profile;
+
+  // How to handle a tap gesture touching multiple targets
+  DidTapMultipleTargetsStrategy did_tap_multiple_targets_strategy;
 };
 
 }  // namespace content