Add code to collect crash data for https://crbug.com/592319.

content/browser/renderer_host/render_widget_host_input_event_router.h

 // Copyright 2015 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.
 
 #ifndef CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_INPUT_EVENT_ROUTER_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_INPUT_EVENT_ROUTER_H_
 
 #include <stdint.h>
 
 #include <deque>
@@ skipping 103 matching lines @@
   SurfaceIdNamespaceOwnerMap owner_map_;
   GestureTargetQueue gesture_target_queue_;
   RenderWidgetHostViewBase* touch_target_;
   RenderWidgetHostViewBase* gesture_target_;
   gfx::Vector2d touch_delta_;
   gfx::Vector2d gesture_delta_;
   int active_touches_;
   std::unordered_map<cc::SurfaceId, HittestData, cc::SurfaceIdHash>
       hittest_data_;
 
+  // Debugging data for https://crbug.com/592319.
+  // Data types declared here to simplify later removal, and understanding of
+  // the code while it's in this intermediate state.
+  static const unsigned kNumLastEventTypes = 5;
+  struct GestureQueueDebugData {
+    unsigned long number_of_gesture_targets_enqueued;
+    unsigned long number_of_gesture_targets_dequeued;
+    int last_gesture_event_types[kNumLastEventTypes];
+    int last_touch_event_types[kNumLastEventTypes];
+    unsigned next_gesture_event_index;
+    unsigned next_touch_event_index;
+
+    GestureQueueDebugData();
+  };
+  GestureQueueDebugData debug_data_;
+
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostInputEventRouter);
   FRIEND_TEST_ALL_PREFIXES(SitePerProcessBrowserTest,
                            InputEventRouterGestureTargetQueueTest);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_INPUT_EVENT_ROUTER_H_