Start of display management for mus

This adds a DisplayManager interface that you get from mus. You can
then attach an observer to observe display related changes.

BUG=548429
TEST=none
R=ben@chromium.org

Committed: https://crrev.com/bc2281a7a7576f5b4da85986298322b3c9d2234e
Cr-Commit-Position: refs/heads/master@{#370880}

Review URL: https://codereview.chromium.org/1615023004

Cr-Commit-Position: refs/heads/master@{#371059}

1 files changed, 6 insertions, 41 deletions

diff --git a/ash/display/screen_ash.cc b/ash/display/screen_ash.cc
index 6008922..477c710 100644
--- a/ash/display/screen_ash.cc
+++ b/ash/display/screen_ash.cc
@@ -17,6 +17,7 @@
 #include "ui/aura/env.h"
 #include "ui/aura/window_event_dispatcher.h"
 #include "ui/gfx/display.h"
+#include "ui/gfx/display_finder.h"
 #include "ui/gfx/screen.h"
 
 namespace ash {
@@ -27,42 +28,6 @@ DisplayManager* GetDisplayManager() {
   return Shell::GetInstance()->display_manager();
 }
 
-gfx::Display FindDisplayNearestPoint(const std::vector<gfx::Display>& displays,
-                                     const gfx::Point& point) {
-  int min_distance = INT_MAX;
-  const gfx::Display* nearest_display = NULL;
-  for (std::vector<gfx::Display>::const_iterator iter = displays.begin();
-       iter != displays.end(); ++iter) {
-    const gfx::Display& display = *iter;
-    int distance = display.bounds().ManhattanDistanceToPoint(point);
-    if (distance < min_distance) {
-      min_distance = distance;
-      nearest_display = &display;
-    }
-  }
-  // There should always be at least one display that is less than INT_MAX away.
-  DCHECK(nearest_display);
-  return *nearest_display;
-}
-
-const gfx::Display* FindDisplayMatching(
-    const std::vector<gfx::Display>& displays,
-    const gfx::Rect& match_rect) {
-  int max_area = 0;
-  const gfx::Display* matching = NULL;
-  for (std::vector<gfx::Display>::const_iterator iter = displays.begin();
-       iter != displays.end(); ++iter) {
-    const gfx::Display& display = *iter;
-    gfx::Rect intersect = gfx::IntersectRects(display.bounds(), match_rect);
-    int area = intersect.width() * intersect.height();
-    if (area > max_area) {
-      max_area = area;
-      matching = &display;
-    }
-  }
-  return matching;
-}
-
 class ScreenForShutdown : public gfx::Screen {
  public:
   explicit ScreenForShutdown(ScreenAsh* screen_ash)
@@ -84,11 +49,11 @@ class ScreenForShutdown : public gfx::Screen {
     return primary_display_;
   }
   gfx::Display GetDisplayNearestPoint(const gfx::Point& point) const override {
-    return FindDisplayNearestPoint(display_list_, point);
+    return *gfx::FindDisplayNearestPoint(display_list_, point);
   }
   gfx::Display GetDisplayMatching(const gfx::Rect& match_rect) const override {
     const gfx::Display* matching =
-        FindDisplayMatching(display_list_, match_rect);
+        gfx::FindDisplayWithBiggestIntersection(display_list_, match_rect);
     // Fallback to the primary display if there is no matching display.
     return matching ? *matching : GetPrimaryDisplay();
   }
@@ -187,14 +152,14 @@ gfx::Display ScreenAsh::GetDisplayNearestPoint(const gfx::Point& point) const {
   // Fallback to the display that has the shortest Manhattan distance from
   // the |point|. This is correct in the only areas that matter, namely in the
   // corners between the physical screens.
-  return FindDisplayNearestPoint(GetDisplayManager()->active_display_list(),
-                                 point);
+  return *gfx::FindDisplayNearestPoint(
+      GetDisplayManager()->active_display_list(), point);
 }
 
 gfx::Display ScreenAsh::GetDisplayMatching(const gfx::Rect& match_rect) const {
   if (match_rect.IsEmpty())
     return GetDisplayNearestPoint(match_rect.origin());
-  const gfx::Display* matching = FindDisplayMatching(
+  const gfx::Display* matching = gfx::FindDisplayWithBiggestIntersection(
       GetDisplayManager()->active_display_list(), match_rect);
   // Fallback to the primary display if there is no matching display.
   return matching ? *matching : GetPrimaryDisplay();