Disallow certain blocking DOM calls during microtask execution.

third_party/WebKit/Source/bindings/templates/methods.cpp

Index: third_party/WebKit/Source/bindings/templates/methods.cpp
diff --git a/third_party/WebKit/Source/bindings/templates/methods.cpp b/third_party/WebKit/Source/bindings/templates/methods.cpp
index 475263f8f2bfd5bded2e420df5aae86bc9376362..f3f60ea048be36c8c621a277fbf5fca944b636fa 100644
--- a/third_party/WebKit/Source/bindings/templates/methods.cpp
+++ b/third_party/WebKit/Source/bindings/templates/methods.cpp
@@ -410,6 +410,10 @@ static void {{overloads.name}}Method{{world_suffix}}(const v8::FunctionCallbackI
             {% if method.deprecate_as and not overloads.deprecate_all_as %}
             Deprecation::countDeprecationIfNotPrivateScript(info.GetIsolate(), currentExecutionContext(info.GetIsolate()), UseCounter::{{method.deprecate_as}});
             {% endif %}
+            {% if method.not_during_microtasks %}
+            if (v8::MicrotasksScope::IsRunningMicrotasks(info.GetIsolate()))
+                return;

[haraken, 2016/05/03 12:10:50]

As Elliott is suggesting in the bug, would it be better to add a console message
here?

+            {% endif %}
             {{method.name}}{{method.overload_index}}Method{{world_suffix}}(info);
             return;
         }
@@ -496,6 +500,10 @@ static void {{method.name}}MethodCallback{{world_suffix}}(const v8::FunctionCall
     {% if method.origin_trial_enabled_function %}
     {{check_origin_trial(method) | indent}}
     {% endif %}
+    {% if method.not_during_microtasks %}
+    if (v8::MicrotasksScope::IsRunningMicrotasks(info.GetIsolate()))
+        return;
+    {% endif %}
     {% endif %}{# not method.overloads #}
     {% if world_suffix in method.activity_logging_world_list %}
     ScriptState* scriptState = ScriptState::from(info.GetIsolate()->GetCurrentContext());