Enable pinch-zoom telemetry on Mac

content/browser/renderer_host/input/synthetic_gesture.cc

 // Copyright 2013 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/browser/renderer_host/input/synthetic_gesture.h"
 
 #include "base/logging.h"
 #include "content/browser/renderer_host/input/synthetic_gesture_target.h"
-#include "content/browser/renderer_host/input/synthetic_pinch_gesture.h"
 #include "content/browser/renderer_host/input/synthetic_smooth_drag_gesture.h"
 #include "content/browser/renderer_host/input/synthetic_smooth_scroll_gesture.h"
 #include "content/browser/renderer_host/input/synthetic_tap_gesture.h"
+#include "content/browser/renderer_host/input/synthetic_touchpad_pinch_gesture.h"
+#include "content/browser/renderer_host/input/synthetic_touchscreen_pinch_gesture.h"
 
 namespace content {
 namespace {
 
 template <typename GestureType, typename GestureParamsType>
 static scoped_ptr<SyntheticGesture> CreateGesture(
     const SyntheticGestureParams& gesture_params) {
   return scoped_ptr<SyntheticGesture>(
       new GestureType(*GestureParamsType::Cast(&gesture_params)));
 }
 
 }  // namespace
 
 SyntheticGesture::SyntheticGesture() {}
 
 SyntheticGesture::~SyntheticGesture() {}
 
 scoped_ptr<SyntheticGesture> SyntheticGesture::Create(
     const SyntheticGestureParams& gesture_params) {
   switch (gesture_params.GetGestureType()) {
     case SyntheticGestureParams::SMOOTH_SCROLL_GESTURE:
       return CreateGesture<SyntheticSmoothScrollGesture,
                            SyntheticSmoothScrollGestureParams>(gesture_params);
     case SyntheticGestureParams::SMOOTH_DRAG_GESTURE:
       return CreateGesture<SyntheticSmoothDragGesture,
                            SyntheticSmoothDragGestureParams>(gesture_params);
     case SyntheticGestureParams::PINCH_GESTURE:
-      return CreateGesture<SyntheticPinchGesture,
-                           SyntheticPinchGestureParams>(gesture_params);
+      // TODO(ericrk): Wire this all the way through to the python/js libraries
+      // and create a SyntheticTouchscreenGestureParams/
+      // SyntheticTouchpadGestureParams, removing the need for any
+      // special-casing.
+      if (SyntheticGestureParams::IsGestureSourceTypeSupported(

[jdduke (slow), 2015/09/22 18:52:37]

Hmm, in theory |gesture_params| can specify either mouse or default, which may
or may not be touch.

We could have a thin SyntheticPinchGesture wrapper, which instantiates the right
implementation lazily (in the first SyntheticPinchGesture::ForwardInputEvents
call), depending on |gesture_params| as well as
|target->GetDefaultSyntheticGestureSourceType()|.

Alternatively, we could get rid of the abstract
GetDefaultSyntheticGestureSourceType() and instead make it a static method on
SyntheticGestureParams (which would allow us to instantiate the right
implementation here).

[ericrk, 2015/09/22 21:46:26]

Makes sense. Went with the thin wrapper approach, as it seemed like pulling
GetDefaultSyntheticGestureSourceType into SyntheticGestureParams as a static
would require additional #ifdef type logic, which seemed a bit uglier? both
would work fine I think.

+              SyntheticGestureParams::TOUCH_INPUT)) {
+        // Only create a touchscreen gesture if we have touch input. If we
+        // report default or mouse input, create a touchpad gesture.
+        return CreateGesture<SyntheticTouchscreenPinchGesture,
+                             SyntheticPinchGestureParams>(gesture_params);
+      } else {
+        return CreateGesture<SyntheticTouchpadPinchGesture,
+                             SyntheticPinchGestureParams>(gesture_params);
+      }
     case SyntheticGestureParams::TAP_GESTURE:
       return CreateGesture<SyntheticTapGesture,
                            SyntheticTapGestureParams>(gesture_params);
   }
   NOTREACHED() << "Invalid synthetic gesture type";
   return scoped_ptr<SyntheticGesture>();
 }
 
 // static
 double SyntheticGesture::ConvertTimestampToSeconds(
     const base::TimeTicks& timestamp) {
   return (timestamp - base::TimeTicks()).InSecondsF();
 }
 
 }  // namespace content