Use low entropy for studies that send experiment IDs to Google properties.

base/test/mock_entropy_provider.h

Index: base/test/mock_entropy_provider.h
diff --git a/base/test/mock_entropy_provider.h b/base/test/mock_entropy_provider.h
index 32e9332e109ebf788c80a3685303e3633487a366..5468461de8aa2f5222dac6e9d14f6e29faf76aab 100644
--- a/base/test/mock_entropy_provider.h
+++ b/base/test/mock_entropy_provider.h
@@ -13,11 +13,19 @@ namespace base {
 
 class MockEntropyProvider : public base::FieldTrial::EntropyProvider {
  public:
+  MockEntropyProvider();
   ~MockEntropyProvider() override;
 
   // base::FieldTrial::EntropyProvider:
   double GetEntropyForTrial(const std::string& trial_name,
                             uint32_t randomization_seed) const override;
+
+  void set_entropy_value(double entropy_value) {

[Alexei Svitkine (slow), 2016/05/18 15:03:29]

Is there any reason to reset it after constructing it? If not, I'd make it a
ctor param.

[jwd, 2016/05/18 18:31:41]

Done.

+    entropy_value_ = entropy_value;
+  }
+
+ private:
+  double entropy_value_;
 };

[Alexei Svitkine (slow), 2016/05/18 15:03:29]

Nit: DISALLOW_COPY_AND_ASSIGN();

[jwd, 2016/05/18 18:31:41]

Done.

 
 }  // namespace base