Make [OriginTrialEnabled] and [RuntimeEnabled] mutually exclusive

third_party/WebKit/Source/bindings/scripts/v8_utilities.py

Index: third_party/WebKit/Source/bindings/scripts/v8_utilities.py
diff --git a/third_party/WebKit/Source/bindings/scripts/v8_utilities.py b/third_party/WebKit/Source/bindings/scripts/v8_utilities.py
index 723bb55c77a94accf20f7910f852acb16beb121a..183763570ceb21108928d84ef7249b514e7e816e 100644
--- a/third_party/WebKit/Source/bindings/scripts/v8_utilities.py
+++ b/third_party/WebKit/Source/bindings/scripts/v8_utilities.py
@@ -366,27 +366,44 @@ def measure_as(definition_or_member, interface):
     return None
 
 
-def runtime_feature_name(definition_or_member):
+# [OriginTrialEnabled]
+def origin_trial_enabled_function_name(definition_or_member, interface):
+    """Returns the name of the OriginTrials enabled function.
+
+    An exception is raised if both the OriginTrialEnabled and RuntimeEnabled
+    extended attributes are applied to the same IDL member. Only one of the
+    two attributes can be applied to any member - they are mutually exclusive.
+
+    The returned function checks if the IDL member should be enabled.
+    Given extended attribute OriginTrialEnabled=FeatureName, return:
+        OriginTrials::{featureName}Enabled
+
+    If the OriginTrialEnabled extended attribute is found, the includes are
+    also updated as a side-effect.
+    """
     extended_attributes = definition_or_member.extended_attributes
-    if 'RuntimeEnabled' not in extended_attributes:
-        return None
-    return extended_attributes['RuntimeEnabled']
+    is_origin_trial_enabled = 'OriginTrialEnabled' in extended_attributes
 
+    if (is_origin_trial_enabled and 'RuntimeEnabled' in extended_attributes):
+        raise Exception('[OriginTrialEnabled] and [RuntimeEnabled] must '
+                        'not be specified on the same definition: '
+                        '%s.%s' % (definition_or_member.idl_name, definition_or_member.name))
 
-def is_origin_trial_enabled(definition_or_member):
-    return 'OriginTrialEnabled' in definition_or_member.extended_attributes
+    if is_origin_trial_enabled:
+        includes.add('core/inspector/ConsoleMessage.h')
+        includes.add('core/origin_trials/OriginTrials.h')
 
+        trial_name = extended_attributes['OriginTrialEnabled']
+        return 'OriginTrials::%sEnabled' % uncapitalize(trial_name)
 
-def origin_trial_name(definition_or_member):
-    return definition_or_member.extended_attributes['OriginTrialEnabled'] if is_origin_trial_enabled(definition_or_member) else None
+    return None
 
 
-def origin_trial_enabled_function(definition_or_member):
-    trial_name = origin_trial_name(definition_or_member)
-    feature_name = runtime_feature_name(definition_or_member)
-    if not feature_name or not trial_name:
-        return
-    return 'OriginTrials::%sEnabled' % uncapitalize(feature_name)
+def runtime_feature_name(definition_or_member):
+    extended_attributes = definition_or_member.extended_attributes
+    if 'RuntimeEnabled' not in extended_attributes:
+        return None
+    return extended_attributes['RuntimeEnabled']
 
 
 # [RuntimeEnabled]
@@ -396,17 +413,16 @@ def runtime_enabled_function_name(definition_or_member):
     The returned function checks if a method/attribute is enabled.
     Given extended attribute RuntimeEnabled=FeatureName, return:
         RuntimeEnabledFeatures::{featureName}Enabled
+
+    If the RuntimeEnabled extended attribute is found, the includes
+    are also updated as a side-effect.
     """
     feature_name = runtime_feature_name(definition_or_member)
 
-    # If an origin trial is on the method/attribute, it overrides the runtime
-    # enabled status. For now, we are unconditionally installing these
-    # attributes/methods, so we are acting as though the runtime enabled
-    # function doesn't exist. (It is checked in the generated OriginTrials
-    # function, instead)
-    trial_name = origin_trial_name(definition_or_member)
-    if not feature_name or trial_name:
+    if not feature_name:
         return
+
+    includes.add('platform/RuntimeEnabledFeatures.h')
     return 'RuntimeEnabledFeatures::%sEnabled' % uncapitalize(feature_name)