PDF Viewer pinch zoom: Update state for zoom in following a zoom out.

pdf/out_of_process_instance.h

Index: pdf/out_of_process_instance.h
diff --git a/pdf/out_of_process_instance.h b/pdf/out_of_process_instance.h
index dbaeb29c86c21253305b440723910d4df27df818..ae1b8e16f519f9d0139869f05e26d1e19a213f84 100644
--- a/pdf/out_of_process_instance.h
+++ b/pdf/out_of_process_instance.h
@@ -249,11 +249,11 @@ class OutOfProcessInstance : public pp::Instance,
 
   // Current zoom factor.
   double zoom_;
-  double initial_zoom_ratio_;
   // True if we request a new bitmap rendering.
   bool needs_reraster_;
-  // Scroll position at the start of a pinch zoom.
-  pp::FloatPoint starting_scroll_offset_;
+  // The scroll position for the last raster, before any transformations are
+  // applied.
+  pp::FloatPoint scroll_offset_at_last_raster_;
   // True if last bitmap was smaller than screen.
   bool last_bitmap_smaller_;
   // Current device scale factor.