Bug 1341531 - Measure input event dispatching latency. (*_EVENT_RECEIVED_MS) r=smaug

This patch measures the time from an input event creation, to it been
dispatched to PresShell, but just before any handler been executed.

MozReview-Commit-ID: 6ZYra7YYICY

--HG--
extra : rebase_source : fb864ab2ec7af3d59f4a4ccf52667f34dcd588d6

layout/base/PresShell.cpp

@@ -8059,10 +8059,14 @@ PresShell::HandleEventInternal(WidgetEvent* aEvent,
             nsPresContext::InteractionType::eKeyInteraction,
             aEvent->mTimeStamp);
         }
+
+        Telemetry::AccumulateTimeDelta(Telemetry::KEYBOARD_EVENT_RECEIVED_MS, aEvent->mTimeStamp);
         break;
       }
       case eMouseDown:
       case eMouseUp:
+        Telemetry::AccumulateTimeDelta(Telemetry::MOUSE_CLICK_EVENT_RECEIVED_MS, aEvent->mTimeStamp);
+        MOZ_FALLTHROUGH;
       case ePointerDown:
       case ePointerUp:
         isHandlingUserInput = true;
@@ -8071,6 +8075,14 @@ PresShell::HandleEventInternal(WidgetEvent* aEvent,
           aEvent->mTimeStamp);
         break;
 
+      case eMouseMove:
+        if (aEvent->mFlags.mHandledByAPZ) {
+          Telemetry::AccumulateTimeDelta(Telemetry::APZ_HANDLED_MOUSE_MOVE_EVENT_RECEIVED_MS, aEvent->mTimeStamp);
+        } else {
+          Telemetry::AccumulateTimeDelta(Telemetry::MOUSE_MOVE_EVENT_RECEIVED_MS, aEvent->mTimeStamp);
+        }
+        break;
+
       case eDrop: {
         nsCOMPtr<nsIDragSession> session = nsContentUtils::GetDragSession();
         if (session) {
@@ -8083,6 +8095,18 @@ PresShell::HandleEventInternal(WidgetEvent* aEvent,
         break;
       }
 
+      case eWheel:
+        if (aEvent->mFlags.mHandledByAPZ) {
+          Telemetry::AccumulateTimeDelta(Telemetry::APZ_HANDLED_WHEEL_EVENT_RECEIVED_MS, aEvent->mTimeStamp);
+        }
+        break;
+
+      case eTouchMove:
+        if (aEvent->mFlags.mHandledByAPZ) {
+          Telemetry::AccumulateTimeDelta(Telemetry::APZ_HANDLED_TOUCH_MOVE_EVENT_RECEIVED_MS, aEvent->mTimeStamp);
+        }
+        break;
+
       default:
         break;
       }

toolkit/components/telemetry/Histograms.json

@@ -11119,5 +11119,59 @@
     "n_buckets": 20,
     "keyed": true,
     "description": "Measures the number of milliseconds we spend waiting on the main thread for IPC messages to serialize their parameters. Note: only messages that take more than 500 microseconds are included in this probe. This probe is keyed on the IPDL message name."
+  },
+  "MOUSE_MOVE_EVENT_RECEIVED_MS": {
+    "alert_emails": ["wpan@mozilla.com"],
+    "expires_in_version": "60",
+    "kind": "exponential",
+    "high": 50000,
+    "n_buckets": 100,
+    "bug_numbers": [1341531],
+    "description": "Time (ms) for the mouse move event to dispatch, but before handlers executing."
+  },
+  "MOUSE_CLICK_EVENT_RECEIVED_MS": {
+    "alert_emails": ["wpan@mozilla.com"],
+    "expires_in_version": "60",
+    "kind": "exponential",
+    "high": 50000,
+    "n_buckets": 100,
+    "bug_numbers": [1341531],
+    "description": "Time (ms) for the mouse click event to dispatch, but before handlers executing."
+  },
+  "KEYBOARD_EVENT_RECEIVED_MS": {
+    "alert_emails": ["wpan@mozilla.com"],
+    "expires_in_version": "60",
+    "kind": "exponential",
+    "high": 50000,
+    "n_buckets": 100,
+    "bug_numbers": [1341531],
+    "description": "Time (ms) for the keyboard event to dispatch, but before handlers executing."
+  },
+  "APZ_HANDLED_TOUCH_MOVE_EVENT_RECEIVED_MS": {
+    "alert_emails": ["wpan@mozilla.com"],
+    "expires_in_version": "60",
+    "kind": "exponential",
+    "high": 50000,
+    "n_buckets": 100,
+    "bug_numbers": [1341531],
+    "description": "Time (ms) for the APZ handled touch move event to dispatch, but before handlers executing."
+  },
+  "APZ_HANDLED_MOUSE_MOVE_EVENT_RECEIVED_MS": {
+    "alert_emails": ["wpan@mozilla.com"],
+    "expires_in_version": "60",
+    "kind": "exponential",
+    "high": 50000,
+    "n_buckets": 100,
+    "bug_numbers": [1341531],
+    "description": "Time (ms) for the APZ handled mouse move event to dispatch, but before handlers executing."
+  },
+  "APZ_HANDLED_WHEEL_EVENT_RECEIVED_MS": {
+    "alert_emails": ["wpan@mozilla.com"],
+    "expires_in_version": "60",
+    "kind": "exponential",
+    "high": 50000,
+    "n_buckets": 100,
+    "bug_numbers": [1341531],
+    "description": "Time (ms) for the APZ handled wheel event to dispatch, but before handlers executing."
   }
 }