Enable pinch-zoom telemetry on Mac

content/browser/renderer_host/input/synthetic_gesture.cc

Index: content/browser/renderer_host/input/synthetic_gesture.cc
diff --git a/content/browser/renderer_host/input/synthetic_gesture.cc b/content/browser/renderer_host/input/synthetic_gesture.cc
index 2e25288dc1359d729aa835a63c965230360865ea..2b981a8703d9c62b9cd62fc53ae92aa2c7a91edf 100644
--- a/content/browser/renderer_host/input/synthetic_gesture.cc
+++ b/content/browser/renderer_host/input/synthetic_gesture.cc
@@ -6,10 +6,11 @@
 
 #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 {
@@ -37,8 +38,20 @@ scoped_ptr<SyntheticGesture> SyntheticGesture::Create(
       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);