Update trackpad pinch-zoom code for corrected scale semantics

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 2481 matching lines @@
 
   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;
+  event.data.pinchUpdate.scale = 1.0f + 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;
+  event.data.pinchUpdate.scale = 1.0f - 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;
+  event.data.pinchUpdate.scale = 1.0f + 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