Rappor: Separate noise params for flags.

Adds support for weak noise, allows the noise parameters for flags to be changed independently from string fields, and makes weak noise for flags the default.

BUG=495712

Review URL: https://codereview.chromium.org/1161163002

Cr-Commit-Position: refs/heads/master@{#332910}

3 files changed, 35 insertions, 14 deletions

diff --git a/tools/metrics/rappor/pretty_print.py b/tools/metrics/rappor/pretty_print.py
index f88e1c3..b5b1ba3 100755
--- a/tools/metrics/rappor/pretty_print.py
+++ b/tools/metrics/rappor/pretty_print.py
@@ -15,18 +15,25 @@ import presubmit_util
 # Model definitions for rappor.xml content
 _SUMMARY_TYPE = models.TextNodeType('summary')
 
+_NOISE_ATTRIBUTES = [
+  'fake-prob',
+  'fake-one-prob',
+  'one-coin-prob',
+  'zero-coin-prob',
+]
+
+_STRING_NOISE_TYPE = models.ObjectNodeType('string-noise',
+    float_attributes=_NOISE_ATTRIBUTES)
+
+_FLAG_NOISE_TYPE = models.ObjectNodeType('flag-noise',
+    float_attributes=_NOISE_ATTRIBUTES)
+
 _PARAMETERS_TYPE = models.ObjectNodeType('parameters',
     int_attributes=[
       'num-cohorts',
       'bytes',
       'hash-functions',
     ],
-    float_attributes=[
-      'fake-prob',
-      'fake-one-prob',
-      'one-coin-prob',
-      'zero-coin-prob',
-    ],
     string_attributes=[
       'reporting-level'
     ])
@@ -37,6 +44,8 @@ _RAPPOR_PARAMETERS_TYPE = models.ObjectNodeType('rappor-parameters',
     children=[
       models.ChildType('summary', _SUMMARY_TYPE, False),
       models.ChildType('parameters', _PARAMETERS_TYPE, False),
+      models.ChildType('stringNoise', _STRING_NOISE_TYPE, False),
+      models.ChildType('flagNoise', _FLAG_NOISE_TYPE, False),
     ])
 
 _RAPPOR_PARAMETERS_TYPES_TYPE = models.ObjectNodeType('rappor-parameter-types',
diff --git a/tools/metrics/rappor/pretty_print_test.py b/tools/metrics/rappor/pretty_print_test.py
index f69b7df..58478dd 100755
--- a/tools/metrics/rappor/pretty_print_test.py
+++ b/tools/metrics/rappor/pretty_print_test.py
@@ -21,9 +21,12 @@ PRETTY_XML = """
   <summary>
     Fake type for tests.
   </summary>
-  <parameters num-cohorts="128" bytes="1" hash-functions="2" fake-prob="0.5"
-      fake-one-prob="0.5" one-coin-prob="0.75" zero-coin-prob="0.25"
+  <parameters num-cohorts="128" bytes="1" hash-functions="2"
       reporting-level="COARSE"/>
+  <string-noise fake-prob="0.5" fake-one-prob="0.5" one-coin-prob="0.75"
+      zero-coin-prob="0.25"/>
+  <flag-noise fake-prob="0.5" fake-one-prob="0.75" one-coin-prob="0.875"
+      zero-coin-prob="0.125"/>
 </rappor-parameters>
 
 </rappor-parameter-types>
diff --git a/tools/metrics/rappor/rappor.xml b/tools/metrics/rappor/rappor.xml
index f457557..a577c1e 100644
--- a/tools/metrics/rappor/rappor.xml
+++ b/tools/metrics/rappor/rappor.xml
@@ -23,9 +23,12 @@ components/rappor/rappor_service.cc.
   <summary>
     Stricter parameters for metrics collected from a broader population.
   </summary>
-  <parameters num-cohorts="128" bytes="1" hash-functions="2" fake-prob="0.5"
-      fake-one-prob="0.5" one-coin-prob="0.75" zero-coin-prob="0.25"
+  <parameters num-cohorts="128" bytes="1" hash-functions="2"
       reporting-level="COARSE"/>
+  <string-noise fake-prob="0.5" fake-one-prob="0.5" one-coin-prob="0.75"
+      zero-coin-prob="0.25"/>
+  <flag-noise fake-prob="0.25" fake-one-prob="0.5" one-coin-prob="0.875"
+      zero-coin-prob="0.125"/>
 </rappor-parameters>
 
 <rappor-parameters name="ETLD_PLUS_ONE">
@@ -33,18 +36,24 @@ components/rappor/rappor_service.cc.
     Deprecated parameters for collecting the domain and registry of a URL from
     UMA opt-in users.
   </summary>
-  <parameters num-cohorts="128" bytes="16" hash-functions="2" fake-prob="0.5"
-      fake-one-prob="0.5" one-coin-prob="0.75" zero-coin-prob="0.25"
+  <parameters num-cohorts="128" bytes="16" hash-functions="2"
       reporting-level="FINE"/>
+  <string-noise fake-prob="0.5" fake-one-prob="0.5" one-coin-prob="0.75"
+      zero-coin-prob="0.25"/>
+  <flag-noise fake-prob="0.25" fake-one-prob="0.5" one-coin-prob="0.875"
+      zero-coin-prob="0.125"/>
 </rappor-parameters>
 
 <rappor-parameters name="UMA_RAPPOR_TYPE">
   <summary>
     Parameters suitable for metrics from UMA opt-in users.
   </summary>
-  <parameters num-cohorts="128" bytes="4" hash-functions="2" fake-prob="0.5"
-      fake-one-prob="0.5" one-coin-prob="0.75" zero-coin-prob="0.25"
+  <parameters num-cohorts="128" bytes="4" hash-functions="2"
       reporting-level="FINE"/>
+  <string-noise fake-prob="0.5" fake-one-prob="0.5" one-coin-prob="0.75"
+      zero-coin-prob="0.25"/>
+  <flag-noise fake-prob="0.25" fake-one-prob="0.5" one-coin-prob="0.875"
+      zero-coin-prob="0.125"/>
 </rappor-parameters>
 
 </rappor-parameter-types>