touch: Fix touch-event hit-testing for multiple touch points.

content/renderer/gpu/input_handler_proxy.cc

 // Copyright (c) 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/renderer/gpu/input_handler_proxy.h"
 
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 #include "content/renderer/gpu/input_handler_proxy_client.h"
 #include "third_party/WebKit/public/platform/Platform.h"
 #include "third_party/WebKit/public/web/WebInputEvent.h"
 #include "ui/events/latency_info.h"
 #include "ui/gfx/frame_time.h"
 
 using blink::WebFloatPoint;
 using blink::WebFloatSize;
 using blink::WebGestureEvent;
 using blink::WebInputEvent;
 using blink::WebMouseEvent;
 using blink::WebMouseWheelEvent;
 using blink::WebPoint;
 using blink::WebTouchEvent;
+using blink::WebTouchPoint;
 
 namespace {
 
 // Validate provided event timestamps that interact with animation timestamps.
 const double kBadTimestampDeltaFromNowInS = 60. * 60. * 24. * 7.;
 
 double InSecondsF(const base::TimeTicks& time) {
   return (time - base::TimeTicks()).InSecondsF();
 }
 
@@ skipping 186 matching lines @@
         *static_cast<const WebGestureEvent*>(&event);
     return HandleGestureFling(gesture_event);
   } else if (event.type == WebInputEvent::GestureFlingCancel) {
     if (CancelCurrentFling())
       return DID_HANDLE;
     else if (!fling_may_be_active_on_main_thread_)
       return DROP_EVENT;
   } else if (event.type == WebInputEvent::TouchStart) {
     const WebTouchEvent& touch_event =
         *static_cast<const WebTouchEvent*>(&event);
-    if (!input_handler_->HaveTouchEventHandlersAt(touch_event.touches[0]
-                                                      .position))
-      return DROP_EVENT;
+    for (unsigned i = 0; i < touch_event.touchesLength; ++i) {

[jamesr, 2013/12/03 00:44:38]

can you use size_t for indexing? unsigned works given how touches[] works, but
it's slightly less idiomatic for a loop counter indexing into an array

[sadrul, 2013/12/03 03:20:00]

Done.

+      if (touch_event.touches[i].state != WebTouchPoint::StatePressed)
+        continue;
+      if (input_handler_->HaveTouchEventHandlersAt(touch_event.touches[i]
+                                                       .position))
+        return DID_NOT_HANDLE;
+    }
+    return DROP_EVENT;
   } else if (WebInputEvent::isKeyboardEventType(event.type)) {
     CancelCurrentFling();
   } else if (event.type == WebInputEvent::MouseMove) {
     const WebMouseEvent& mouse_event =
         *static_cast<const WebMouseEvent*>(&event);
     // TODO(tony): Ignore when mouse buttons are down?
     input_handler_->MouseMoveAt(gfx::Point(mouse_event.x, mouse_event.y));
   }
 
   return DID_NOT_HANDLE;
@@ skipping 224 matching lines @@
   TRACE_EVENT2("renderer",
                "InputHandlerProxy::notifyCurrentFlingVelocity",
                "vx",
                velocity.width,
                "vy",
                velocity.height);
   input_handler_->NotifyCurrentFlingVelocity(ToClientScrollIncrement(velocity));
 }
 
 }  // namespace content