Migrate from MathUtil::inverse() to gfx::Transform::GetInverse()

cc/layer_impl.cc

 // Copyright 2011 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 "cc/layer_impl.h"
 
 #include "base/debug/trace_event.h"
 #include "base/stringprintf.h"
 #include "base/values.h"
 #include "cc/debug_border_draw_quad.h"
@@ skipping 218 matching lines @@
         return InputHandlerClient::ScrollOnMainThread;
     }
 
     if (!screenSpaceTransform().IsInvertible()) {
         TRACE_EVENT0("cc", "LayerImpl::tryScroll: Ignored nonInvertibleTransform");
         return InputHandlerClient::ScrollIgnored;
     }
 
     if (!nonFastScrollableRegion().IsEmpty()) {
         bool clipped = false;
-        gfx::PointF hitTestPointInContentSpace = MathUtil::projectPoint(MathUtil::inverse(screenSpaceTransform()), screenSpacePoint, clipped);
+        gfx::Transform inverseScreenSpaceTransform(gfx::Transform::kSkipInitialization);
+        screenSpaceTransform().GetInverse(&inverseScreenSpaceTransform);

[danakj, 2012/12/19 05:23:06]

If GetInverse() returns false, seems like we shouldn't use it? Should we pretend
the region is empty in that case, and cause impl scrolling when it might not
expect? Or pretend the region is infinite and scroll on the main thread when we
might have been ok to impl scroll? I guess the latter is safer?

+        gfx::PointF hitTestPointInContentSpace = MathUtil::projectPoint(inverseScreenSpaceTransform, screenSpacePoint, clipped);
         gfx::PointF hitTestPointInLayerSpace = gfx::ScalePoint(hitTestPointInContentSpace, 1 / contentsScaleX(), 1 / contentsScaleY());
         if (!clipped && nonFastScrollableRegion().Contains(gfx::ToRoundedPoint(hitTestPointInLayerSpace))) {
             TRACE_EVENT0("cc", "LayerImpl::tryScroll: Failed nonFastScrollableRegion");
             return InputHandlerClient::ScrollOnMainThread;
         }
     }
 
     if (type == InputHandlerClient::Wheel && haveWheelEventHandlers()) {
         TRACE_EVENT0("cc", "LayerImpl::tryScroll: Failed wheelEventHandlers");
         return InputHandlerClient::ScrollOnMainThread;
@@ skipping 532 matching lines @@
 
 void LayerImpl::setVerticalScrollbarLayer(ScrollbarLayerImpl* scrollbarLayer)
 {
     if (!m_scrollbarAnimationController)
         m_scrollbarAnimationController = ScrollbarAnimationController::create(this);
     m_scrollbarAnimationController->setVerticalScrollbarLayer(scrollbarLayer);
     m_scrollbarAnimationController->updateScrollOffset(this);
 }
 
 }  // namespace cc