Move DisplayUtils methods into gfx::Screen.

These methods are currently just used by metrics.  I moved
them from base into the browser a while back, but I think it
makes the most sense for them to live in gfx::Screen.  I'm
also relocating the tests to ui_unittest and making them work
on Aura.

BUG=99711,100341
TEST=ran ui_unittest

Review URL: http://codereview.chromium.org/8382019

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@107027 0039d316-1c4b-4281-b951-d872f2087c98

6 files changed, 137 insertions, 6 deletions

diff --git a/ui/gfx/screen.h b/ui/gfx/screen.h
index 0c712d47..45a15ad 100644
--- a/ui/gfx/screen.h
+++ b/ui/gfx/screen.h
@@ -9,6 +9,7 @@
 #include "ui/gfx/native_widget_types.h"
 #include "ui/gfx/point.h"
 #include "ui/gfx/rect.h"
+#include "ui/gfx/size.h"
 
 namespace gfx {
 
@@ -26,6 +27,7 @@ class UI_EXPORT Screen {
   static void SetInstance(Screen* screen);
 #endif
 
+  // Returns the current absolute position of the mouse pointer.
   static gfx::Point GetCursorScreenPoint();
 
   // Returns the work area of the monitor nearest the specified window.
@@ -44,6 +46,14 @@ class UI_EXPORT Screen {
   // Returns the window under the cursor.
   static gfx::NativeWindow GetWindowAtCursorScreenPoint();
 
+  // Returns the dimensions of the primary monitor in pixels.
+  static gfx::Size GetPrimaryMonitorSize();
+
+  // Returns the number of monitors.
+  // Mirrored displays are excluded; this method is intended to return the
+  // number of distinct, usable displays.
+  static int GetNumMonitors();
+
  protected:
   virtual gfx::Point GetCursorScreenPointImpl() = 0;
   virtual gfx::Rect GetMonitorWorkAreaNearestWindowImpl(
@@ -54,6 +64,8 @@ class UI_EXPORT Screen {
       const gfx::Point& point) = 0;
   virtual gfx::Rect GetMonitorAreaNearestPointImpl(const gfx::Point& point) = 0;
   virtual gfx::NativeWindow GetWindowAtCursorScreenPointImpl() = 0;
+  virtual gfx::Size GetPrimaryMonitorSizeImpl() = 0;
+  virtual int GetNumMonitorsImpl() = 0;
 
 private:
 #if defined(USE_AURA)
diff --git a/ui/gfx/screen_aura.cc b/ui/gfx/screen_aura.cc
index 097fe8c..0093af6 100644
--- a/ui/gfx/screen_aura.cc
+++ b/ui/gfx/screen_aura.cc
@@ -24,38 +24,42 @@ void Screen::SetInstance(Screen* screen) {
 
 // static
 gfx::Point Screen::GetCursorScreenPoint() {
-  DCHECK(instance_);
   return instance_->GetCursorScreenPointImpl();
 }
 
 // static
 gfx::Rect Screen::GetMonitorWorkAreaNearestWindow(gfx::NativeWindow window) {
-  DCHECK(instance_);
   return instance_->GetMonitorWorkAreaNearestWindowImpl(window);
 }
 
 // static
 gfx::Rect Screen::GetMonitorAreaNearestWindow(gfx::NativeWindow window) {
-  DCHECK(instance_);
   return instance_->GetMonitorAreaNearestWindowImpl(window);
 }
 
 // static
 gfx::Rect Screen::GetMonitorWorkAreaNearestPoint(const gfx::Point& point) {
-  DCHECK(instance_);
   return instance_->GetMonitorWorkAreaNearestPointImpl(point);
 }
 
 // static
 gfx::Rect Screen::GetMonitorAreaNearestPoint(const gfx::Point& point) {
-  DCHECK(instance_);
   return instance_->GetMonitorAreaNearestPointImpl(point);
 }
 
 // static
 gfx::NativeWindow Screen::GetWindowAtCursorScreenPoint() {
-  DCHECK(instance_);
   return instance_->GetWindowAtCursorScreenPointImpl();
 }
 
+// static
+gfx::Size Screen::GetPrimaryMonitorSize() {
+  return instance_->GetPrimaryMonitorSizeImpl();
+}
+
+// static
+int Screen::GetNumMonitors() {
+  return instance_->GetNumMonitorsImpl();
+}
+
 }  // namespace gfx
diff --git a/ui/gfx/screen_gtk.cc b/ui/gfx/screen_gtk.cc
index 81904e1..42799b7 100644
--- a/ui/gfx/screen_gtk.cc
+++ b/ui/gfx/screen_gtk.cc
@@ -63,6 +63,7 @@ gfx::Rect Screen::GetMonitorAreaNearestPoint(const gfx::Point& point) {
   return gfx::Rect(bounds);
 }
 
+// static
 gfx::NativeWindow Screen::GetWindowAtCursorScreenPoint() {
   GdkWindow* window = gdk_window_at_pointer(NULL, NULL);
   if (!window)
@@ -77,4 +78,18 @@ gfx::NativeWindow Screen::GetWindowAtCursorScreenPoint() {
   return GTK_IS_WINDOW(widget) ? GTK_WINDOW(widget) : NULL;
 }
 
+// static
+gfx::Size Screen::GetPrimaryMonitorSize() {
+  GdkScreen* screen = gdk_screen_get_default();
+  return gfx::Size(gdk_screen_get_width(screen), gdk_screen_get_height(screen));
+}
+
+// static
+int Screen::GetNumMonitors() {
+  // This query is kinda bogus for Linux -- do we want number of X screens?
+  // The number of monitors Xinerama has?  We'll just use whatever GDK uses.
+  GdkScreen* screen = gdk_screen_get_default();
+  return gdk_screen_get_n_monitors(screen);
+}
+
 }  // namespace gfx
diff --git a/ui/gfx/screen_mac.mm b/ui/gfx/screen_mac.mm
index b38344a..6bf0992 100644
--- a/ui/gfx/screen_mac.mm
+++ b/ui/gfx/screen_mac.mm
@@ -4,6 +4,7 @@
 
 #include "ui/gfx/screen.h"
 
+#import <ApplicationServices/ApplicationServices.h>
 #import <Cocoa/Cocoa.h>
 
 namespace gfx {
@@ -17,4 +18,46 @@ gfx::Point Screen::GetCursorScreenPoint() {
   return gfx::Point(mouseLocation.x, mouseLocation.y);
 }
 
+// static
+gfx::Size Screen::GetPrimaryMonitorSize() {
+  CGDirectDisplayID main_display = CGMainDisplayID();
+  return gfx::Size(CGDisplayPixelsWide(main_display),
+                   CGDisplayPixelsHigh(main_display));
+}
+
+// static
+int Screen::GetNumMonitors() {
+  // Don't just return the number of online displays.  It includes displays
+  // that mirror other displays, which are not desired in the count.  It's
+  // tempting to use the count returned by CGGetActiveDisplayList, but active
+  // displays exclude sleeping displays, and those are desired in the count.
+
+  // It would be ridiculous to have this many displays connected, but
+  // CGDirectDisplayID is just an integer, so supporting up to this many
+  // doesn't hurt.
+  CGDirectDisplayID online_displays[128];
+  CGDisplayCount online_display_count = 0;
+  if (CGGetOnlineDisplayList(arraysize(online_displays),
+                             online_displays,
+                             &online_display_count) != kCGErrorSuccess) {
+    // 1 is a reasonable assumption.
+    return 1;
+  }
+
+  int display_count = 0;
+  for (CGDisplayCount online_display_index = 0;
+       online_display_index < online_display_count;
+       ++online_display_index) {
+    CGDirectDisplayID online_display = online_displays[online_display_index];
+    if (CGDisplayMirrorsDisplay(online_display) == kCGNullDirectDisplay) {
+      // If this display doesn't mirror any other, include it in the count.
+      // The primary display in a mirrored set will be counted, but those that
+      // mirror it will not be.
+      ++display_count;
+    }
+  }
+
+  return display_count;
+}
+
 }  // namespace gfx
diff --git a/ui/gfx/screen_unittest.cc b/ui/gfx/screen_unittest.cc
new file mode 100644
index 0000000..4b1a572
--- /dev/null
+++ b/ui/gfx/screen_unittest.cc
@@ -0,0 +1,45 @@
+// Copyright (c) 2011 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 "testing/gtest/include/gtest/gtest.h"
+#include "ui/gfx/screen.h"
+
+#if defined(USE_AURA)
+#include "base/message_loop.h"
+#include "ui/aura/desktop.h"
+#endif
+
+namespace {
+
+#if defined(USE_AURA)
+class ScreenTest : public testing::Test {
+ public:
+  ScreenTest() {
+    aura::Desktop::GetInstance()->ShowDesktop();
+  }
+
+  virtual ~ScreenTest() {
+    aura::Desktop::GetInstance()->DeleteInstanceForTesting();
+  }
+
+ private:
+  MessageLoopForUI message_loop_;
+};
+#else
+typedef testing::Test ScreenTest;
+#endif
+
+TEST_F(ScreenTest, GetPrimaryMonitorSize) {
+  // We aren't actually testing that it's correct, just that it's sane.
+  const gfx::Size size = gfx::Screen::GetPrimaryMonitorSize();
+  EXPECT_GE(size.width(), 1);
+  EXPECT_GE(size.height(), 1);
+}
+
+TEST_F(ScreenTest, GetNumMonitors) {
+  // We aren't actually testing that it's correct, just that it's sane.
+  EXPECT_GE(gfx::Screen::GetNumMonitors(), 1);
+}
+
+}  // namespace
diff --git a/ui/gfx/screen_win.cc b/ui/gfx/screen_win.cc
index 530cebe..2873b72 100644
--- a/ui/gfx/screen_win.cc
+++ b/ui/gfx/screen_win.cc
@@ -54,9 +54,21 @@ gfx::Rect Screen::GetMonitorAreaNearestPoint(const gfx::Point& point) {
   return GetMonitorAreaOrWorkAreaNearestPoint(point, false);
 }
 
+// static
 gfx::NativeWindow Screen::GetWindowAtCursorScreenPoint() {
   POINT location;
   return GetCursorPos(&location) ? WindowFromPoint(location) : NULL;
 }
 
+// static
+gfx::Size Screen::GetPrimaryMonitorSize() {
+  return gfx::Size(GetSystemMetrics(SM_CXSCREEN),
+                   GetSystemMetrics(SM_CYSCREEN));
+}
+
+// static
+int Screen::GetNumMonitors() {
+  return GetSystemMetrics(SM_CMONITORS);
+}
+
 }  // namespace gfx