MouseMove when the mouse is down to signal compositor priority

content/renderer/scheduler/renderer_scheduler_impl.cc

Index: content/renderer/scheduler/renderer_scheduler_impl.cc
diff --git a/content/renderer/scheduler/renderer_scheduler_impl.cc b/content/renderer/scheduler/renderer_scheduler_impl.cc
index 4ffe487b3764faa5abac556b86425a6f6469ee7b..abed6053221b51038e22fdc0c9f8a5f05c55fe9f 100644
--- a/content/renderer/scheduler/renderer_scheduler_impl.cc
+++ b/content/renderer/scheduler/renderer_scheduler_impl.cc
@@ -120,14 +120,23 @@ void RendererSchedulerImpl::DidCommitFrameToCompositor() {
 }
 
 void RendererSchedulerImpl::DidReceiveInputEventOnCompositorThread(
-    blink::WebInputEvent::Type type) {
+    const blink::WebInputEvent& web_input_event) {
   TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("renderer.scheduler"),
                "RendererSchedulerImpl::DidReceiveInputEventOnCompositorThread");
-  // Ignore mouse events because on windows these can very frequent.
+  // We regard MouseMove events with the left mouse button down as a signsal

[rmcilroy, 2015/02/06 10:19:34]

/s/signsal/signal

[alex clarke (OOO till 29th), 2015/02/06 10:25:32]

Done.

+  // that the user is doing something requiring a smooth frame rate.
+  if (web_input_event.type == blink::WebInputEvent::MouseMove &&
+      (web_input_event.modifiers & blink::WebInputEvent::LeftButtonDown)) {
+    UpdateForInputEvent();
+    return;
+  }
+  // Ignore all other mouse events becuase they probably don't signal user

[rmcilroy, 2015/02/06 10:19:33]

/s/becuase/because

[alex clarke (OOO till 29th), 2015/02/06 10:25:32]

Done.

+  // interaction needing a smooth framerate. NOTE isMouseEventType returns false
+  // for mouse wheel events, hence we regard them as user input.
   // Ignore keyboard events because it doesn't really make sense to enter
   // compositor priority for them.
-  if (blink::WebInputEvent::isMouseEventType(type) ||
-      blink::WebInputEvent::isKeyboardEventType(type)) {
+  if (blink::WebInputEvent::isMouseEventType(web_input_event.type) ||
+      blink::WebInputEvent::isKeyboardEventType(web_input_event.type)) {
     return;
   }
   UpdateForInputEvent();