Articulate the cancel behavior in the WebTouchEvent.

content/renderer/input/render_widget_input_handler.cc

 // 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.
 
 #include "content/renderer/input/render_widget_input_handler.h"
 
 #include <stddef.h>
 #include <stdint.h>
 #include <utility>
 
@@ skipping 103 matching lines @@
   }
 
 #undef CASE_TYPE
 }
 
 void LogPassiveLatency(int64_t latency) {
   UMA_HISTOGRAM_CUSTOM_COUNTS("Event.PassiveListeners.Latency", latency, 1,
                               10000000, 100);
 }
 
 void LogPassiveEventListenersUma(WebInputEventResult result,

[tdresser, 2016/04/18 15:12:02]

Could we add some kind of test for this? Worst case we just expose this, and
test this method directly, using base/test/histogram_tester.h.

[dtapuska, 2016/04/18 19:19:33]

Done.

-                                 bool non_blocking,
-                                 bool cancelable,
+                                 WebInputEvent::DispatchType dispatch_type,
                                  double event_timestamp,
                                  const ui::LatencyInfo& latency_info) {
   enum {
     PASSIVE_LISTENER_UMA_ENUM_PASSIVE,
     PASSIVE_LISTENER_UMA_ENUM_UNCANCELABLE,
     PASSIVE_LISTENER_UMA_ENUM_SUPPRESSED,
     PASSIVE_LISTENER_UMA_ENUM_CANCELABLE,
     PASSIVE_LISTENER_UMA_ENUM_CANCELABLE_AND_CANCELED,
+    PASSIVE_LISTENER_UMA_ENUM_FORCED_NON_BLOCKING,
     PASSIVE_LISTENER_UMA_ENUM_COUNT
   };
 
   int enum_value;
-  if (non_blocking)
-    enum_value = PASSIVE_LISTENER_UMA_ENUM_PASSIVE;
-  else if (!cancelable)
-    enum_value = PASSIVE_LISTENER_UMA_ENUM_UNCANCELABLE;
-  else if (result == WebInputEventResult::HandledApplication)
-    enum_value = PASSIVE_LISTENER_UMA_ENUM_CANCELABLE_AND_CANCELED;
-  else if (result == WebInputEventResult::HandledSuppressed)
-    enum_value = PASSIVE_LISTENER_UMA_ENUM_SUPPRESSED;
-  else
-    enum_value = PASSIVE_LISTENER_UMA_ENUM_CANCELABLE;
+  switch (dispatch_type) {
+    case WebInputEvent::NonBlockingForced:
+      enum_value = PASSIVE_LISTENER_UMA_ENUM_FORCED_NON_BLOCKING;
+      break;
+    case WebInputEvent::NonBlockingPassive:
+      enum_value = PASSIVE_LISTENER_UMA_ENUM_PASSIVE;
+      break;
+    case WebInputEvent::NonBlocking:
+      enum_value = PASSIVE_LISTENER_UMA_ENUM_UNCANCELABLE;
+      break;
+    case WebInputEvent::Blocking:
+      if (result == WebInputEventResult::HandledApplication)
+        enum_value = PASSIVE_LISTENER_UMA_ENUM_CANCELABLE_AND_CANCELED;
+      else if (result == WebInputEventResult::HandledSuppressed)
+        enum_value = PASSIVE_LISTENER_UMA_ENUM_SUPPRESSED;
+      else
+        enum_value = PASSIVE_LISTENER_UMA_ENUM_CANCELABLE;
+      break;
+    default:
+      NOTREACHED();
+      return;
+  }
 
   UMA_HISTOGRAM_ENUMERATION("Event.PassiveListeners", enum_value,
                             PASSIVE_LISTENER_UMA_ENUM_COUNT);
 
   if (enum_value == PASSIVE_LISTENER_UMA_ENUM_CANCELABLE &&
       base::TimeTicks::IsHighResolution()) {
     base::TimeTicks now = base::TimeTicks::Now();
     LogPassiveLatency(GetEventLatencyMicros(event_timestamp, now));
   }
 }
@@ skipping 139 matching lines @@
 
   WebInputEventResult processed = prevent_default
                                       ? WebInputEventResult::HandledSuppressed
                                       : WebInputEventResult::NotHandled;
   if (input_event.type != WebInputEvent::Char || !suppress_next_char_events_) {
     suppress_next_char_events_ = false;
     if (processed == WebInputEventResult::NotHandled && widget_->webwidget())
       processed = widget_->webwidget()->handleInputEvent(input_event);
   }
 
-  bool non_blocking =
-      dispatch_type ==
-          InputEventDispatchType::DISPATCH_TYPE_NON_BLOCKING_NOTIFY_MAIN ||
-      dispatch_type == InputEventDispatchType::DISPATCH_TYPE_NON_BLOCKING;
   // TODO(dtapuska): Use the input_event.timeStampSeconds as the start
   // ideally this should be when the event was sent by the compositor to the
   // renderer. crbug.com/565348
   if (input_event.type == WebInputEvent::TouchStart ||
       input_event.type == WebInputEvent::TouchMove ||
       input_event.type == WebInputEvent::TouchEnd) {
     LogPassiveEventListenersUma(
-        processed, non_blocking,
-        static_cast<const WebTouchEvent&>(input_event).cancelable,
+        processed, static_cast<const WebTouchEvent&>(input_event).dispatchType,
         input_event.timeStampSeconds, latency_info);
   } else if (input_event.type == WebInputEvent::MouseWheel) {
-    LogPassiveEventListenersUma(processed, non_blocking, !non_blocking,
-                                input_event.timeStampSeconds, latency_info);
+    bool non_blocking =
+        dispatch_type ==
+            InputEventDispatchType::DISPATCH_TYPE_NON_BLOCKING_NOTIFY_MAIN ||

[tdresser, 2016/04/18 15:12:03]

Would it be clearer to negate this boolean?

[dtapuska, 2016/04/18 19:19:33]

can I leave this for now. It is going away in a follow on patch where I add the
dispatch type for wheel events.

[tdresser, 2016/04/18 19:40:45]

SGTM.

+        dispatch_type == InputEventDispatchType::DISPATCH_TYPE_NON_BLOCKING;
+    LogPassiveEventListenersUma(
+        processed,
+        non_blocking ? WebInputEvent::NonBlocking : WebInputEvent::Blocking,
+        input_event.timeStampSeconds, latency_info);
   }
 
   // If this RawKeyDown event corresponds to a browser keyboard shortcut and
   // it's not processed by webkit, then we need to suppress the upcoming Char
   // events.
   bool is_keyboard_shortcut =
       input_event.type == WebInputEvent::RawKeyDown &&
       static_cast<const WebKeyboardEvent&>(input_event).isBrowserShortcut;
   if (processed == WebInputEventResult::NotHandled && is_keyboard_shortcut)
     suppress_next_char_events_ = true;
@@ skipping 197 matching lines @@
   if (pending_input_event_ack_) {
     TRACE_EVENT_ASYNC_END0("input",
                            "RenderWidgetInputHandler::ThrottledInputEventAck",
                            pending_input_event_ack_.get());
     delegate_->OnInputEventAck(std::move(pending_input_event_ack_));
   }
   total_input_handling_time_this_frame_ = base::TimeDelta();
 }
 
 }  // namespace content