Handle mac trackpad zoom via GesturePinch events

content/browser/web_contents/web_contents_impl_unittest.cc

 // Copyright (c) 2012 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 "base/logging.h"
 #include "base/strings/utf_string_conversions.h"
 #include "content/browser/frame_host/cross_site_transferring_request.h"
 #include "content/browser/frame_host/interstitial_page_impl.h"
 #include "content/browser/frame_host/navigation_entry_impl.h"
 #include "content/browser/renderer_host/render_view_host_impl.h"
@@ skipping 2412 matching lines @@
   // Unless there is no vertical movement.
   dy = 0;
   event = SyntheticWebMouseWheelEventBuilder::Build(2, dy, modifiers, false);
   EXPECT_FALSE(contents()->HandleWheelEvent(event));
   EXPECT_EQ(0, delegate->GetAndResetContentsZoomChangedCallCount());
 
   // Ensure pointers to the delegate aren't kept beyond it's lifetime.
   contents()->SetDelegate(NULL);
 }
 
+// Tests that trackpad GesturePinchUpdate events get turned into browser zoom.
+TEST_F(WebContentsImplTest, HandleGestureEvent) {
+  using blink::WebGestureEvent;
+  using blink::WebInputEvent;
+
+  scoped_ptr<ContentsZoomChangedDelegate> delegate(
+      new ContentsZoomChangedDelegate());
+  contents()->SetDelegate(delegate.get());
+
+  const float kZoomStepValue = 0.6f;
+  blink::WebGestureEvent event = SyntheticWebGestureEventBuilder::Build(
+      WebInputEvent::GesturePinchUpdate, WebGestureEvent::Touchpad);
+
+  // A pinch less than the step value doesn't change the zoom level.
+  event.data.pinchUpdate.scale = kZoomStepValue * 0.8f;
+  EXPECT_TRUE(contents()->HandleGestureEvent(event));
+  EXPECT_EQ(0, delegate->GetAndResetContentsZoomChangedCallCount());
+
+  // But repeating the event so the combined scale is greater does.
+  EXPECT_TRUE(contents()->HandleGestureEvent(event));
+  EXPECT_EQ(1, delegate->GetAndResetContentsZoomChangedCallCount());
+  EXPECT_TRUE(delegate->last_zoom_in());
+
+  // Pinching back out one step goes back to 100%.
+  event.data.pinchUpdate.scale = -kZoomStepValue;
+  EXPECT_TRUE(contents()->HandleGestureEvent(event));
+  EXPECT_EQ(1, delegate->GetAndResetContentsZoomChangedCallCount());
+  EXPECT_FALSE(delegate->last_zoom_in());
+
+  // Pinching out again doesn't zoom (step is twice as large around 100%).
+  EXPECT_TRUE(contents()->HandleGestureEvent(event));
+  EXPECT_EQ(0, delegate->GetAndResetContentsZoomChangedCallCount());
+
+  // And again now it zooms once per step.
+  EXPECT_TRUE(contents()->HandleGestureEvent(event));
+  EXPECT_EQ(1, delegate->GetAndResetContentsZoomChangedCallCount());
+  EXPECT_FALSE(delegate->last_zoom_in());
+
+  // No other type of gesture event is handled by WebContentsImpl (for example
+  // a touchscreen pinch gesture).
+  event = SyntheticWebGestureEventBuilder::Build(
+      WebInputEvent::GesturePinchUpdate, WebGestureEvent::Touchscreen);
+  event.data.pinchUpdate.scale = kZoomStepValue * 3;
+  EXPECT_FALSE(contents()->HandleGestureEvent(event));
+  EXPECT_EQ(0, delegate->GetAndResetContentsZoomChangedCallCount());
+
+  // Ensure pointers to the delegate aren't kept beyond it's lifetime.
+  contents()->SetDelegate(NULL);
+}
+
 }  // namespace content