Fix scrollbar painting problems in pdf files in HiDPI mode with fractional scales.

pdf/instance.cc

 // Copyright (c) 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 "pdf/instance.h"
 
 #include <algorithm>  // for min()
 #define _USE_MATH_DEFINES  // for M_PI
 #include <cmath>      // for log() and pow()
 #include <math.h>
@@ skipping 936 matching lines @@
       return;
     }
   }
 
   pp::Rect location_dip = location;
   ScaleRect(1.0f / device_scale_, &location_dip);
 
   DCHECK(!image_data_.is_null());
   widget->Paint(location_dip, &image_data_);
 
-  // Re-scale the rectangle from DIPs to device pixels, so we ensure that we
-  // don't miss any pixels due to rounding outwards in ScaleRect.
-  location = location_dip;
-  ScaleRect(device_scale_, &location);
-
   ready->push_back(PaintManager::ReadyRect(location, image_data_, true));
 }
 
 void Instance::OnTimerFired(int32_t) {
   HandleInputEvent(last_mouse_event_);
 }
 
 void Instance::OnClientTimerFired(int32_t id) {
   engine_->OnCallback(id);
 }
@@ skipping 1747 matching lines @@
   return instance_->HasScriptableMethod(name, exception);
 }
 
 pp::Var PDFScriptableObject::Call(const pp::Var& method,
                                   const std::vector<pp::Var>& args,
                                   pp::Var* exception) {
   return instance_->CallScriptableMethod(method, args, exception);
 }
 
 }  // namespace chrome_pdf