Add the partial screen magnifier to Chrome OS.

cc/CCRenderSurfaceFilters.cpp

 // 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 "config.h"
 
 #if USE(ACCELERATED_COMPOSITING)
 
 #include "CCRenderSurfaceFilters.h"
 
@@ skipping 402 matching lines @@
             SkAutoTUnref<SkImageFilter> zoomFilter(
                 new SkMagnifierImageFilter(
                     SkRect::MakeXYWH(op.zoomRect().x,
                                      op.zoomRect().y,
                                      op.zoomRect().width,
                                      op.zoomRect().height),
                     op.amount()));
             paint.setImageFilter(zoomFilter.get());
             canvas->saveLayer(0, &paint);
             canvas->drawBitmap(state.source(), 0, 0);
+            canvas->restore();
             break;
         }
         case WebKit::WebFilterOperation::FilterTypeBrightness:
         case WebKit::WebFilterOperation::FilterTypeContrast:
         case WebKit::WebFilterOperation::FilterTypeGrayscale:
         case WebKit::WebFilterOperation::FilterTypeSepia:
         case WebKit::WebFilterOperation::FilterTypeSaturate:
         case WebKit::WebFilterOperation::FilterTypeHueRotate:
         case WebKit::WebFilterOperation::FilterTypeInvert:
         case WebKit::WebFilterOperation::FilterTypeOpacity:
             ASSERT_NOT_REACHED();
             break;
         }
         state.swap();
     }
     context3D->flush();
     return state.source();
 }
 
 }
 #endif // USE(ACCELERATED_COMPOSITING)