[DevTools] Ignore TouchEmulator::CancelTouch calls when disabled.

content/browser/renderer_host/input/touch_emulator_unittest.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop.h"
 #include "base/time/time.h"
@@ skipping 534 matching lines @@
 
   MouseDown(100, 200);
   EXPECT_EQ("TouchStart GestureTapDown", ExpectedEvents());
   MouseUp(200, 200);
   EXPECT_EQ(
       "TouchMove GestureTapCancel GestureScrollBegin GestureScrollUpdate"
       " TouchEnd GestureScrollEnd",
       ExpectedEvents());
 }
 
+TEST_F(TouchEmulatorTest, CancelAfterDisableDoesNotCrash) {
+  DisableSynchronousTouchAck();
+  MouseDown(100, 200);
+  emulator()->Disable();
+  EXPECT_EQ("TouchStart TouchCancel", ExpectedEvents());
+  emulator()->CancelTouch();
+}
+
 }  // namespace content