posix: move mac-specific code into mac-specific file

base/sys_info_mac.cc

Index: base/sys_info_mac.cc
diff --git a/base/sys_info_mac.cc b/base/sys_info_mac.cc
index 54b73205f0920d52475310bc9e49e72d48082d76..7d3a17d80b6de09c1b3e108ba2b2819222c5132b 100644
--- a/base/sys_info_mac.cc
+++ b/base/sys_info_mac.cc
@@ -4,7 +4,10 @@
 
 #include "base/sys_info.h"
 
+#include <ApplicationServices/ApplicationServices.h>
 #include <CoreServices/CoreServices.h>
+#include <mach/mach_host.h>
+#include <mach/mach_init.h>
 
 namespace base {
 
@@ -20,4 +23,65 @@ void SysInfo::OperatingSystemVersionNumbers(int32 *major_version,
       reinterpret_cast<SInt32*>(bugfix_version));
 }
 
+// static
+int64 SysInfo::AmountOfPhysicalMemory() {
+  struct host_basic_info hostinfo;
+  mach_msg_type_number_t count = HOST_BASIC_INFO_COUNT;
+  int result = host_info(mach_host_self(),
+                         HOST_BASIC_INFO,
+                         reinterpret_cast<host_info_t>(&hostinfo),
+                         &count);
+  DCHECK_EQ(HOST_BASIC_INFO_COUNT, count);
+  if (result != KERN_SUCCESS) {
+    NOTREACHED();
+    return 0;
+  }
+
+  return static_cast<int64>(hostinfo.max_mem);
+}
+
+// static
+void SysInfo::GetPrimaryDisplayDimensions(int* width, int* height) {
+  CGDirectDisplayID main_display = CGMainDisplayID();
+  if (width)
+    *width = CGDisplayPixelsWide(main_display);
+  if (height)
+    *height = CGDisplayPixelsHigh(main_display);
+}
+
+// static
+int SysInfo::DisplayCount() {
+  // 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 base