Default to the same Cargo features in all build commands

Fixes #8308 and #7327.

python/servo/build_commands.py

@@ -147,7 +147,7 @@ class MachCommands(CommandBase):
               features=None, android=None, verbose=False, debug_mozjs=False, params=None):
         if android is None:
             android = self.config["build"]["android"]
-        features = features or []
+        features = features or self.servo_features()
 
         opts = params or []
 
@@ -194,7 +194,7 @@ class MachCommands(CommandBase):
 
         self.ensure_bootstrapped(target=target)
 
-        if debug_mozjs or self.config["build"]["debug-mozjs"]:
+        if debug_mozjs:
             features += ["script/debugmozjs"]
 
         if features:
@@ -265,6 +265,10 @@ class MachCommands(CommandBase):
         if release:
             opts += ["--release"]
 
+        servo_features = self.servo_features()
+        if servo_features:
+            opts += ["--features", "%s" % ' '.join("servo/" + x for x in servo_features)]
+
         build_start = time()
         with cd(path.join("ports", "cef")):
             ret = call(["cargo", "build"] + opts,

python/servo/command_base.py

@@ -415,6 +415,13 @@ class CommandBase(object):
     def servo_crate(self):
         return path.join(self.context.topdir, "components", "servo")
 
+    def servo_features(self):
+        """Return a list of optional features to enable for the Servo crate"""
+        features = []
+        if self.config["build"]["debug-mozjs"]:
+            features += ["script/debugmozjs"]
+        return features
+
     def android_support_dir(self):
         return path.join(self.context.topdir, "support", "android")
 

python/servo/testing_commands.py

@@ -178,6 +178,10 @@ class MachCommands(CommandBase):
             args += ["-p", "%s_tests" % crate]
         args += test_patterns
 
+        features = self.servo_features()
+        if features:
+            args += ["--features", "%s" % ' '.join(features)]
+
         env = self.build_env()
         env["RUST_BACKTRACE"] = "1"