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

cc/direct_renderer.cc

 // Copyright 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 "cc/direct_renderer.h"
 
 #include <vector>
 
 #include "base/debug/trace_event.h"
 #include "base/metrics/histogram.h"
@@ skipping 167 matching lines @@
     renderPassesInDrawOrder.clear();
 }
 
 gfx::RectF DirectRenderer::computeScissorRectForRenderPass(const DrawingFrame& frame)
 {
     gfx::RectF renderPassScissor = frame.currentRenderPass->output_rect;
 
     if (frame.rootDamageRect == frame.rootRenderPass->output_rect)
         return renderPassScissor;
 
-    gfx::Transform inverseTransform = MathUtil::inverse(frame.currentRenderPass->transform_to_root_target);
-    gfx::RectF damageRectInRenderPassSpace = MathUtil::projectClippedRect(inverseTransform, frame.rootDamageRect);
-    renderPassScissor.Intersect(damageRectInRenderPassSpace);
+    gfx::Transform inverseTransform(gfx::Transform::kSkipInitialization);
+    if (frame.currentRenderPass->transform_to_root_target.GetInverse(&inverseTransform)) {
+        // Only intersect inverse-projected damage if the transform is invertible.
+        gfx::RectF damageRectInRenderPassSpace = MathUtil::projectClippedRect(inverseTransform, frame.rootDamageRect);
+        renderPassScissor.Intersect(damageRectInRenderPassSpace);
+    }
 
     return renderPassScissor;
 }
 
 void DirectRenderer::setScissorStateForQuad(const DrawingFrame& frame, const DrawQuad& quad)
 {
     if (quad.isClipped()) {
         gfx::RectF quadScissorRect = quad.clipRect();
         setScissorTestRect(moveScissorToWindowSpace(frame, quadScissorRect));
     }
@@ skipping 93 matching lines @@
     return pass->output_rect.size();
 }
 
 // static
 GLenum DirectRenderer::renderPassTextureFormat(const RenderPass*)
 {
     return GL_RGBA;
 }
 
 }  // namespace cc