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

pdf/out_of_process_instance.cc

Index: pdf/out_of_process_instance.cc
diff --git a/pdf/out_of_process_instance.cc b/pdf/out_of_process_instance.cc
index 2b271b5bf2f592d598a5de67dede7e76967cb101..efcd4e659fbc6cce2218741be6c9ab76289280fd 100644
--- a/pdf/out_of_process_instance.cc
+++ b/pdf/out_of_process_instance.cc
@@ -497,6 +497,12 @@ void OutOfProcessInstance::HandleMessage(const pp::Var& message) {
       paint_manager_.ClearTransform();
       last_bitmap_smaller_ = false;
       needs_reraster_ = true;
+
+      // If we're zooming out, we need to update |starting_scroll_offset_| and
+      // |initial_zoom_ratio_|, in case the user continues the gesture by
+      // zooming in.
+      starting_scroll_offset_ = scroll_offset;

[bokan, 2017/03/28 14:26:26]

These two variables are the offset/zoom since last raster, right? Please update
the comment on starting_scroll_offset_ to make that more clear (and add a
similar comment on initial_zoom_ratio_) if that's right.

[Kevin McNee, 2017/03/28 22:55:26]

So it turns out that |initial_zoom_ratio_| is redundant since |zoom_| gives us
all the information we need, so I've gone ahead and removed it entirely. Also,
I've renamed |starting_scroll_offset_| to |scroll_offset_at_last_raster_| to
better describe its purpose.

Still LGTM?

+      initial_zoom_ratio_ = zoom_ratio;
     }
 
     // Bound the input parameters.