(Mac) Implement about:memory.

chrome/chrome.gyp

Index: chrome/chrome.gyp
diff --git a/chrome/chrome.gyp b/chrome/chrome.gyp
index 7bda7a445191da6078de977862e1ce0808d1915b..cb66f4f7badb4b301505315f202c5284ba5ee499 100755
--- a/chrome/chrome.gyp
+++ b/chrome/chrome.gyp
@@ -1716,6 +1716,7 @@
         'browser/login_prompt_win.cc',
         'browser/memory_details.cc',
         'browser/memory_details_linux.cc',
+        'browser/memory_details_mac.cc',
         'browser/memory_details_win.cc',
         'browser/memory_details.h',
         'browser/memory_purger.cc',
@@ -1874,6 +1875,8 @@
         'browser/privacy_blacklist/blacklist_store.cc',
         'browser/privacy_blacklist/blocked_response.h',
         'browser/privacy_blacklist/blocked_response.cc',
+        'browser/process_info_snapshot_mac.cc',
+        'browser/process_info_snapshot.h',
         'browser/process_singleton.h',
         'browser/process_singleton_linux.cc',
         'browser/process_singleton_mac.cc',
@@ -4544,6 +4547,7 @@
         'browser/privacy_blacklist/blacklist_manager_unittest.cc',
         'browser/privacy_blacklist/blacklist_unittest.cc',
         'browser/privacy_blacklist/blacklist_io_unittest.cc',
+        'browser/process_info_snapshot_mac_unittest.cc',
         'browser/profile_manager_unittest.cc',
         'browser/renderer_host/audio_renderer_host_unittest.cc',
         'browser/renderer_host/file_system_accessor_unittest.cc',