Fix code around display overscan settings.

ash/display/multi_display_manager.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 "ash/display/multi_display_manager.h"
 
 #include <string>
 #include <vector>
 
 #include "ash/display/display_controller.h"
@@ skipping 108 matching lines @@
     const aura::Window* window,
     const gfx::Insets& insets) {
   const RootWindow* root = window->GetRootWindow();
   gfx::Display& display = FindDisplayForRootWindow(root);
   gfx::Rect old_work_area = display.work_area();
   display.UpdateWorkAreaFromInsets(insets);
   return old_work_area != display.work_area();
 }
 
 const gfx::Display& MultiDisplayManager::GetDisplayForId(int64 id) const {
-  for (DisplayList::const_iterator iter = displays_.begin();
-       iter != displays_.end(); ++iter) {
-    if ((*iter).id() == id)
-      return *iter;
-  }
-  VLOG(1) << "display not found for id:" << id;
-  return GetInvalidDisplay();
+  return const_cast<MultiDisplayManager*>(this)->FindDisplayForId(id);
 }
 
 const gfx::Display& MultiDisplayManager::FindDisplayContainingPoint(
     const gfx::Point& point_in_screen) const {
   for (DisplayList::const_iterator iter = displays_.begin();
        iter != displays_.end(); ++iter) {
     const gfx::Display& display = *iter;
     if (display.bounds().Contains(point_in_screen))
       return display;
   }
   return GetInvalidDisplay();
 }
 
 void MultiDisplayManager::SetOverscanInsets(int64 display_id,
                                             const gfx::Insets& insets_in_dip) {
+  std::map<int64, gfx::Insets>::const_iterator old_overscan =
+      overscan_mapping_.find(display_id);
+  if (old_overscan != overscan_mapping_.end()) {
+    gfx::Insets old_insets = old_overscan->second;
+    gfx::Display& display = FindDisplayForId(display_id);
+    if (display.is_valid()) {
+      // Undo the existing insets before applying the new insets.
+      gfx::Rect bounds = display.bounds_in_pixel();
+      bounds.Inset(old_insets.Scale(-display.device_scale_factor()));
+      display.SetScaleAndBounds(display.device_scale_factor(), bounds);
+    }
+  }
   overscan_mapping_[display_id] = insets_in_dip;
   OnNativeDisplaysChanged(displays_);
 }
 
 void MultiDisplayManager::OnNativeDisplaysChanged(
     const std::vector<gfx::Display>& updated_displays) {
   if (updated_displays.empty()) {
     // Don't update the displays when all displays are disconnected.
     // This happens when:
     // - the device is idle and powerd requested to turn off all displays.
@@ skipping 269 matching lines @@
     new_displays.push_back(display);
   }
   OnNativeDisplaysChanged(new_displays);
 }
 
 gfx::Display& MultiDisplayManager::FindDisplayForRootWindow(
     const aura::RootWindow* root_window) {
   int64 id = root_window->GetProperty(kDisplayIdKey);
   // if id is |kInvaildDisplayID|, it's being deleted.
   DCHECK(id != gfx::Display::kInvalidDisplayID);
-  return FindDisplayForId(id);
+  gfx::Display& display = FindDisplayForId(id);
+  DCHECK(display.is_valid());
+  return display;
 }
 
 gfx::Display& MultiDisplayManager::FindDisplayForId(int64 id) {
   for (DisplayList::iterator iter = displays_.begin();
        iter != displays_.end(); ++iter) {
     if ((*iter).id() == id)
       return *iter;
   }
-  DLOG(FATAL) << "Could not find display:" << id;
+  DLOG(WARNING) << "Could not find display:" << id;
   return GetInvalidDisplay();
 }
 
 void MultiDisplayManager::AddDisplayFromSpec(const std::string& spec) {
   gfx::Display display = CreateDisplayFromSpec(spec);
 
   const gfx::Insets insets = display.GetWorkAreaInsets();
   const gfx::Rect& native_bounds = display.bounds_in_pixel();
   display.SetScaleAndBounds(display.device_scale_factor(), native_bounds);
   display.UpdateWorkAreaFromInsets(insets);
@@ skipping 11 matching lines @@
   DisplayList::iterator iter_to_update = to_update->begin();
   DisplayList::const_iterator iter = displays_.begin();
   for (; iter != displays_.end() && iter_to_update != to_update->end();
        ++iter, ++iter_to_update) {
     (*iter_to_update).set_id((*iter).id());
   }
 }
 
 }  // namespace internal
 }  // namespace ash