Revert of Remove enable/disable wheel gestures setting.

content/browser/renderer_host/input/input_router_impl_unittest.cc

Index: content/browser/renderer_host/input/input_router_impl_unittest.cc
diff --git a/content/browser/renderer_host/input/input_router_impl_unittest.cc b/content/browser/renderer_host/input/input_router_impl_unittest.cc
index deb16ec308a28da422e71a30ac033c48aa849504..84bc82d86eb4dd24cc1496299f2093a378c46a12 100644
--- a/content/browser/renderer_host/input/input_router_impl_unittest.cc
+++ b/content/browser/renderer_host/input/input_router_impl_unittest.cc
@@ -170,6 +170,18 @@
     browser_context_.reset();
   }
 
+  void SetUpForGestureBasedWheelScrolling(bool enabled) {
+    CHECK(!base::CommandLine::ForCurrentProcess()->HasSwitch(
+              switches::kDisableWheelGestures) &&
+          !base::CommandLine::ForCurrentProcess()->HasSwitch(
+              switches::kEnableWheelGestures));
+    base::CommandLine::ForCurrentProcess()->AppendSwitch(
+        enabled ? switches::kEnableWheelGestures
+                : switches::kDisableWheelGestures);
+    TearDown();
+    SetUp();
+  }
+
   void SetUpForTouchAckTimeoutTest(int desktop_timeout_ms,
                                    int mobile_timeout_ms) {
     config_.touch_config.desktop_touch_ack_timeout_delay =
@@ -935,6 +947,44 @@
 #endif  // defined(USE_AURA)
 
 TEST_F(InputRouterImplTest, UnhandledWheelEvent) {
+  SetUpForGestureBasedWheelScrolling(false);
+
+  // Simulate wheel events.
+  SimulateWheelEvent(0, 0, 0, -5, 0, false);   // sent directly
+  SimulateWheelEvent(0, 0, 0, -10, 0, false);  // enqueued
+
+  // Check that only the first event was sent.
+  EXPECT_TRUE(process_->sink().GetUniqueMessageMatching(
+                  InputMsg_HandleInputEvent::ID));
+  EXPECT_EQ(1U, GetSentMessageCountAndResetSink());
+
+  // Indicate that the wheel event was unhandled.
+  SendInputEventACK(WebInputEvent::MouseWheel,
+                    INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
+
+  // Check that the correct unhandled wheel event was received.
+  EXPECT_EQ(1U, ack_handler_->GetAndResetAckCount());
+  EXPECT_EQ(INPUT_EVENT_ACK_STATE_NOT_CONSUMED, ack_handler_->ack_state());
+  EXPECT_EQ(ack_handler_->acked_wheel_event().deltaY, -5);
+
+  // Check that the second event was sent.
+  EXPECT_TRUE(process_->sink().GetUniqueMessageMatching(
+                  InputMsg_HandleInputEvent::ID));
+  EXPECT_EQ(1U, GetSentMessageCountAndResetSink());
+
+  // Indicate that the wheel event was unhandled.
+  SendInputEventACK(WebInputEvent::MouseWheel,
+                    INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
+
+  // Check that the correct unhandled wheel event was received.
+  EXPECT_EQ(1U, ack_handler_->GetAndResetAckCount());
+  EXPECT_EQ(INPUT_EVENT_ACK_STATE_NOT_CONSUMED, ack_handler_->ack_state());
+  EXPECT_EQ(ack_handler_->acked_wheel_event().deltaY, -10);
+}
+
+TEST_F(InputRouterImplTest, UnhandledWheelEventWithGestureScrolling) {
+  SetUpForGestureBasedWheelScrolling(true);
+
   // Simulate wheel events.
   SimulateWheelEvent(0, 0, 0, -5, 0, false);   // sent directly
   SimulateWheelEvent(0, 0, 0, -10, 0, false);  // enqueued