Notify Blink about start of gesture scroll through a queued event.

content/common/input/touch_event_stream_validator.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 "content/common/input/touch_event_stream_validator.h"
 
 #include "base/logging.h"
 #include "base/strings/stringprintf.h"
 #include "content/common/input/web_input_event_traits.h"
 #include "content/common/input/web_touch_event_traits.h"
@@ skipping 30 matching lines @@
 }
 
 TouchEventStreamValidator::~TouchEventStreamValidator() {
 }
 
 bool TouchEventStreamValidator::Validate(const WebTouchEvent& event,
                                          std::string* error_msg) {
   DCHECK(error_msg);
   error_msg->clear();
 
+  // TouchScrollStarted is not part of a regular touch event stream.
+  if (event.type == WebInputEvent::TouchScrollStarted)
+    return true;
+
   WebTouchEvent previous_event = previous_event_;
   previous_event_ = event;
 
   if (!event.touchesLength) {
     error_msg->append("Touch event is empty.\n");
     return false;
   }
 
   if (!WebInputEvent::isTouchEventType(event.type)) {
     error_msg->append(StringPrintf("Touch event has invalid type: %s\n",
@@ skipping 95 matching lines @@
   if (!found_valid_state_for_type) {
     error_msg->append(
         StringPrintf("No valid touch point corresponding to event type: %s\n",
                      WebInputEventTraits::GetName(event.type)));
   }
 
   return error_msg->empty();
 }
 
 }  // namespace content