Add discardable memory emulation for non-android/mac platforms

base/base.gyp

Index: base/base.gyp
diff --git a/base/base.gyp b/base/base.gyp
index 85c97518d4e5d640338802f3de8348ccf53b7dbd..e962df123886075c7d31599093b9cbdbccbfeaa8 100644
--- a/base/base.gyp
+++ b/base/base.gyp
@@ -517,6 +517,7 @@
         'md5_unittest.cc',
         'memory/aligned_memory_unittest.cc',
         'memory/discardable_memory_unittest.cc',
+        'memory/discardable_memory_provider_unittest.cc',
         'memory/linked_ptr_unittest.cc',
         'memory/ref_counted_memory_unittest.cc',
         'memory/ref_counted_unittest.cc',
@@ -806,6 +807,11 @@
             'third_party/nspr/nspr.gyp:nspr',
           ],
         }],
+        ['OS == "mac" or OS == "android"', {
+          'sources!': [
+            'memory/discardable_memory_unittest.cc',
+          ],
+        }],
       ],  # conditions
       'target_conditions': [
         ['OS == "ios" and _toolset != "host"', {