base/allocator: Hardcode TCMalloc optimization level to 2 on Windows.

TCMalloc is very slow in debug mode. Testing this out on Linux demonstrates
clear wins, so I'm hopeful Windows will similarly improve. This change mostly
copies the same configuration from ffmpeg, which unifies the setting of the
optimization level variables in target_defaults.

BUG=388949

Review URL: https://codereview.chromium.org/437163006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@287454 0039d316-1c4b-4281-b951-d872f2087c98

base/allocator/allocator.gyp

@@ -3,6 +3,16 @@
 # found in the LICENSE file.
 
 {
+  'target_defaults': {
+    'variables': {
+      # This code gets run a lot and debugged rarely, so it should be fast
+      # by default. See http://crbug.com/388949.
+      'debug_optimize': '2',
+      'win_debug_Optimization': '2',
+      # Run time checks are incompatible with any level of optimizations.
+      'win_debug_RuntimeChecks': '0',
+    },
+  },
   'variables': {
     'tcmalloc_dir': '../../third_party/tcmalloc/chromium',
     'use_vtable_verify%': 0,
@@ -306,9 +316,6 @@
             # e.g. for profiling (it's more rare to profile Debug builds,
             # but people sometimes need to do that).
             'disable_debugallocation%': 0,
-            # This code gets run a lot and debugged rarely, so it should be fast
-            # by default. See http://crbug.com/388949.
-            'debug_optimize': 2,
           },
           'conditions': [
             # TODO(phajdan.jr): Also enable on Windows.