assistedinject: Skip static methods on interfaces.

This fixes google/guice#937.

extensions/assistedinject/src/com/google/inject/assistedinject/FactoryProvider2#FactoryProvider2(Key[F],BindingCollector).mjava

@@ -23,6 +23,11 @@
       ImmutableMap.Builder<Method, AssistData> assistDataBuilder = ImmutableMap.builder();
       // TODO: also grab methods from superinterfaces
       for (Method method : factoryRawType.getMethods()) {
+        // Skip static methods
+        if (Modifier.isStatic(method.getModifiers())) {
+          continue;
+        }
+
         // Skip default methods that java8 may have created.
         if (isDefault(method) && (method.isBridge() || method.isSynthetic())) {
           // Even synthetic default methods need the return type validation...

jdk8-tests/test/com/google/inject/jdk8/StaticInterfaceMethodsTest#testAssistedInjection().mjava

@@ -0,0 +1,11 @@
+  public void testAssistedInjection() {
+    Injector injector = Guice.createInjector(new AbstractModule() {
+      @Override
+      protected void configure() {
+        install(new FactoryModuleBuilder().build(Factory.class));
+      }
+    });
+    Factory factory = injector.getInstance(Factory.class);
+    assertEquals(1, factory.create(1).i);
+  }
+

jdk8-tests/test/com/google/inject/jdk8/StaticInterfaceMethodsTest.Factory#create(int).mjava

@@ -0,0 +1,2 @@
+    Thing create(int i);
+

jdk8-tests/test/com/google/inject/jdk8/StaticInterfaceMethodsTest.Factory#getDefault().mjava

@@ -0,0 +1,4 @@
+    static Factory getDefault() {
+      return Thing::new;
+    }
+

jdk8-tests/test/com/google/inject/jdk8/StaticInterfaceMethodsTest.Thing#Thing(int).mjava

@@ -0,0 +1,5 @@
+    @Inject
+    Thing(@Assisted int i) {
+      this.i = i;
+    }
+