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 e35e6b1e71759e785ce897a537dbbe0eed5a16d7..2383167ca5316ab2f5bf0175ffdf35dc5efce3b5 100644
--- a/base/base.gyp
+++ b/base/base.gyp
@@ -513,6 +513,7 @@
         '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',
@@ -802,6 +803,11 @@
             '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"', {