Add support for pressure on pointer events

The touch demo needs some basic smoothing, right now
it looks rather jittery after this change.  But the pressure
code is definitely working!

R=abarth@chromium.org
BUG=

Review URL: https://codereview.chromium.org/970493003

examples/touch-demo.sky

@@ -4,10 +4,11 @@
 <style>
 dot {
     position: absolute;
-    height: 100px;
-    width: 100px;
+    height: 10px;
+    width: 10px;
     background-color: #00FF00;
-    border-radius: 50px;
+    border-radius: 5px;
+    opacity: .75;
 }
 </style>
 <log>Ready!</log>
@@ -46,8 +47,12 @@ void stopDots(event) {
 }
 
 void runToTheCenter(event) {
-  whichDot(event).style["transform"] =
-      "translate(${event.x-50}px,${event.y-50}px)";
+  float radius = (5 + (95 * event.pressure));
+  Element dot = whichDot(event);
+  dot.style["transform"] = "translate(${event.x-radius}px,${event.y-radius}px)";
+  dot.style["width"] = "${2 * radius}px";
+  dot.style["height"] = "${2 * radius}px";
+  dot.style["border-radius"] = "${radius}px";
 }
 
 void main() {

shell/org/domokit/sky/shell/PlatformView.java

@@ -112,11 +112,19 @@ public class PlatformView extends SurfaceView
         pointerData.x = event.getX(pointerIndex);
         pointerData.y = event.getY(pointerIndex);
 
+        pointerData.pressure = event.getPressure(pointerIndex);
+        // TODO(eseidel): Could get the calibrated range if necessary:
+        // event.getDevice().getMotionRange(MotionEvent.AXIS_PRESSURE)
+        pointerData.pressureMin = 0.0f;
+        pointerData.pressureMax = 1.0f;
+
         InputEvent inputEvent = new InputEvent();
         inputEvent.type = getTypeForAction(event.getActionMasked());
         inputEvent.timeStamp = event.getEventTime();
         inputEvent.pointerData = pointerData;
 
+
+
         mViewportObserver.onInputEvent(inputEvent);
     }
 

shell/ui/input_event_converter.cc

@@ -41,6 +41,9 @@ scoped_ptr<blink::WebInputEvent> BuildWebPointerEvent(
     web_event->pointer = event->pointer_data->pointer;
     web_event->x = event->pointer_data->x / device_pixel_ratio;
     web_event->y = event->pointer_data->y / device_pixel_ratio;
+    web_event->pressure = event->pointer_data->pressure;
+    web_event->pressureMin = event->pointer_data->pressure_min;
+    web_event->pressureMax = event->pointer_data->pressure_max;
   }
 
   return web_event.Pass();