Support hardware_class filtering in variations for ChromeOS devices.

BUG=366807

Review URL: https://codereview.chromium.org/259663002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@267741 0039d316-1c4b-4281-b951-d872f2087c98

10 files changed, 159 insertions, 20 deletions

diff --git a/chrome/browser/metrics/variations/variations_service.cc b/chrome/browser/metrics/variations/variations_service.cc
index 4d3aec7..e8fe57d 100644
--- a/chrome/browser/metrics/variations/variations_service.cc
+++ b/chrome/browser/metrics/variations/variations_service.cc
@@ -12,6 +12,7 @@
 #include "base/metrics/sparse_histogram.h"
 #include "base/prefs/pref_registry_simple.h"
 #include "base/prefs/pref_service.h"
+#include "base/sys_info.h"
 #include "base/version.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/network_time/network_time_tracker.h"
@@ -156,7 +157,7 @@ ResourceRequestsAllowedState ResourceRequestStateToHistogramValue(
 }
 
 
-// Get current form factor and convert it from enum DeviceFormFactor to enum
+// Gets current form factor and converts it from enum DeviceFormFactor to enum
 // Study_FormFactor.
 Study_FormFactor GetCurrentFormFactor() {
   switch (ui::GetDeviceFormFactor()) {
@@ -171,6 +172,15 @@ Study_FormFactor GetCurrentFormFactor() {
   return Study_FormFactor_DESKTOP;
 }
 
+// Gets the hardware class and returns it as a string. This returns an empty
+// string if the client is not ChromeOS.
+std::string GetHardwareClass() {
+#if defined(OS_CHROMEOS)
+  return base::SysInfo::GetLsbReleaseBoard();
+#endif  // OS_CHROMEOS
+  return std::string();
+}
+
 // Returns the date that should be used by the VariationsSeedProcessor to do
 // expiry and start date checks.
 base::Time GetReferenceDateForExpiryChecks(PrefService* local_state) {
@@ -230,7 +240,7 @@ bool VariationsService::CreateTrialsFromSeed() {
   VariationsSeedProcessor().CreateTrialsFromSeed(
       seed, g_browser_process->GetApplicationLocale(),
       GetReferenceDateForExpiryChecks(local_state_), current_version,
-      GetChannelForVariations(), GetCurrentFormFactor());
+      GetChannelForVariations(), GetCurrentFormFactor(), GetHardwareClass());
 
   // Log the "freshness" of the seed that was just used. The freshness is the
   // time between the last successful seed download and now.
diff --git a/components/variations/proto/study.proto b/components/variations/proto/study.proto
index 384c0ec..28ac183 100644
--- a/components/variations/proto/study.proto
+++ b/components/variations/proto/study.proto
@@ -146,7 +146,7 @@ message Study {
   // Filtering criteria specifying whether this study is applicable to a given
   // Chrome instance.
   //
-  // Next tag: 8
+  // Next tag: 10
   message Filter {
     // The start date of the study in Unix time format. (Seconds since midnight
     // January 1, 1970 UTC). See: http://en.wikipedia.org/wiki/Unix_time
@@ -186,6 +186,22 @@ message Study {
     // applies to all form factors.
     // Ex: [PHONE, TABLET]
     repeated FormFactor form_factor = 7;
+
+    // List of ChromeOS hardware classes that will receive this study. Each
+    // entry is treated as a substring of the actual device hardware_class,
+    // so "FOO" will match the client's hardware class "Device FOOBAR". If
+    // omitted, the study applies to all hardware classes unless
+    // |exclude_hardware_class| is specified. Mutually exclusive with
+    // |exclude_hardware_class|.
+    repeated string hardware_class = 8;
+
+    // List of ChromeOS hardware classes that will be excluded in this
+    // study. Each entry is treated as a substring of the actual device
+    // hardware_class, so "FOO" will match the client's hardware class
+    // "Device FOOBAR". If omitted, the study applies to all hardware classes
+    // unless |hardware_class| is specified. Mutually exclusive with
+    // |hardware_class|.
+    repeated string exclude_hardware_class = 9;
   }
 
   // Filtering criteria for this study. A study that is filtered out for a given
diff --git a/components/variations/study_filtering.cc b/components/variations/study_filtering.cc
index aeb36cc..7f35e18 100644
--- a/components/variations/study_filtering.cc
+++ b/components/variations/study_filtering.cc
@@ -64,6 +64,41 @@ bool CheckStudyFormFactor(const Study_Filter& filter,
   return false;
 }
 
+bool CheckStudyHardwareClass(const Study_Filter& filter,
+                             const std::string& hardware_class) {
+  // Empty hardware_class and exclude_hardware_class matches all.
+  if (filter.hardware_class_size() == 0 &&
+      filter.exclude_hardware_class_size() == 0) {
+    return true;
+  }
+
+  // Checks if we are supposed to filter for a specified set of
+  // hardware_classes. Note that this means this overrides the
+  // exclude_hardware_class in case that ever occurs (which it shouldn't).
+  if (filter.hardware_class_size() > 0) {
+    for (int i = 0; i < filter.hardware_class_size(); ++i) {
+      // Check if the entry is a substring of |hardware_class|.
+      size_t position = hardware_class.find(filter.hardware_class(i));
+      if (position != std::string::npos)
+        return true;
+    }
+    // None of the requested hardware_classes match.
+    return false;
+  }
+
+  // Omit if matches any of the exclude entries.
+  for (int i = 0; i < filter.exclude_hardware_class_size(); ++i) {
+    // Check if the entry is a substring of |hardware_class|.
+    size_t position = hardware_class.find(
+        filter.exclude_hardware_class(i));
+    if (position != std::string::npos)
+      return false;
+  }
+
+  // None of the exclusions match, so this accepts.
+  return true;
+}
+
 bool CheckStudyLocale(const Study_Filter& filter, const std::string& locale) {
   // An empty locale list matches all locales.
   if (filter.locale_size() == 0)
@@ -130,7 +165,8 @@ bool ShouldAddStudy(
     const base::Time& reference_date,
     const base::Version& version,
     Study_Channel channel,
-    Study_FormFactor form_factor) {
+    Study_FormFactor form_factor,
+    const std::string& hardware_class) {
   if (study.has_filter()) {
     if (!CheckStudyChannel(study.filter(), channel)) {
       DVLOG(1) << "Filtered out study " << study.name() << " due to channel.";
@@ -163,6 +199,13 @@ bool ShouldAddStudy(
                   " due to start date.";
       return false;
     }
+
+    if (!CheckStudyHardwareClass(study.filter(), hardware_class)) {
+      DVLOG(1) << "Filtered out study " << study.name() <<
+                  " due to hardware_class.";
+      return false;
+    }
+
   }
 
   DVLOG(1) << "Kept study " << study.name() << ".";
@@ -178,6 +221,7 @@ void FilterAndValidateStudies(
     const base::Version& version,
     Study_Channel channel,
     Study_FormFactor form_factor,
+    const std::string& hardware_class,
     std::vector<ProcessedStudy>* filtered_studies) {
   DCHECK(version.IsValid());
 
@@ -191,7 +235,7 @@ void FilterAndValidateStudies(
   for (int i = 0; i < seed.study_size(); ++i) {
     const Study& study = seed.study(i);
     if (!internal::ShouldAddStudy(study, locale, reference_date, version,
-                                  channel, form_factor)) {
+                                  channel, form_factor, hardware_class)) {
       continue;
     }
 
diff --git a/components/variations/study_filtering.h b/components/variations/study_filtering.h
index 1c14fc9..bb8b09d 100644
--- a/components/variations/study_filtering.h
+++ b/components/variations/study_filtering.h
@@ -28,6 +28,11 @@ bool CheckStudyChannel(const Study_Filter& filter, Study_Channel channel);
 bool CheckStudyFormFactor(const Study_Filter& filter,
                           Study_FormFactor form_factor);
 
+// Checks whether a study is applicable for the given |hardware_class| per
+// |filter|.
+bool CheckStudyHardwareClass(const Study_Filter& filter,
+                             const std::string& hardware_class);
+
 // Checks whether a study is applicable for the given |locale| per |filter|.
 bool CheckStudyLocale(const Study_Filter& filter, const std::string& locale);
 
@@ -46,15 +51,14 @@ bool CheckStudyVersion(const Study_Filter& filter,
 bool IsStudyExpired(const Study& study, const base::Time& date_time);
 
 // Returns whether |study| should be disabled according to its restriction
-// parameters. Uses |version_info| for min / max version checks,
-// |reference_date| for the start date check and |channel| for channel
-// checks.
+// parameters.
 bool ShouldAddStudy(const Study& study,
                     const std::string& locale,
                     const base::Time& reference_date,
                     const base::Version& version,
                     Study_Channel channel,
-                    Study_FormFactor form_factor);
+                    Study_FormFactor form_factor,
+                    const std::string& hardware_class);
 
 }  // namespace internal
 
@@ -67,6 +71,7 @@ void FilterAndValidateStudies(const VariationsSeed& seed,
                               const base::Version& version,
                               Study_Channel channel,
                               Study_FormFactor form_factor,
+                              const std::string& hardware_class,
                               std::vector<ProcessedStudy>* filtered_studies);
 
 }  // namespace chrome_variations
diff --git a/components/variations/study_filtering_unittest.cc b/components/variations/study_filtering_unittest.cc
index 84c5cf7..ff39d80 100644
--- a/components/variations/study_filtering_unittest.cc
+++ b/components/variations/study_filtering_unittest.cc
@@ -313,6 +313,65 @@ TEST(VariationsStudyFilteringTest, CheckStudyVersion) {
   }
 }
 
+TEST(VariationsStudyFilteringTest, CheckStudyHardwareClass) {
+  struct {
+    const char* hardware_class;
+    const char* exclude_hardware_class;
+    const char* actual_hardware_class;
+    bool expected_result;
+  } test_cases[] = {
+    // Neither filtered nor excluded set:
+    // True since empty is always a match.
+    {"", "", "fancy INTEL pear device", true},
+    {"", "", "", true},
+
+    // Filtered set:
+    {"apple,pear,orange", "", "apple", true},
+    {"apple,pear,orange", "", "fancy INTEL pear device", true},
+    {"apple,pear,orange", "", "fancy INTEL GRAPE device", false},
+    // Somehow tagged as both, but still valid.
+    {"apple,pear,orange", "", "fancy INTEL pear GRAPE device", true},
+    // Substring, so still valid.
+    {"apple,pear,orange", "", "fancy INTEL SNapple device", true},
+    // No issues with doubling.
+    {"apple,pear,orange", "", "fancy orange orange device", true},
+    // Empty, which is what would happen for non ChromeOS platforms.
+    {"apple,pear,orange", "", "", false},
+
+    // Excluded set:
+    {"", "apple,pear,orange", "apple", false},
+    {"", "apple,pear,orange", "fancy INTEL pear device", false},
+    {"", "apple,pear,orange", "fancy INTEL GRAPE device", true},
+    // Somehow tagged as both. Very excluded!
+    {"", "apple,pear,orange", "fancy INTEL pear GRAPE device", false},
+    // Substring, so still invalid.
+    {"", "apple,pear,orange", "fancy INTEL SNapple device", false},
+    // Empty.
+    {"", "apple,pear,orange", "", true},
+
+    // Not testing when both are set as it should never occur and should be
+    // considered undefined.
+  };
+
+  for (size_t i = 0; i < ARRAYSIZE_UNSAFE(test_cases); ++i) {
+    Study_Filter filter;
+    std::vector<std::string> hardware_class;
+    base::SplitString(test_cases[i].hardware_class, ',', &hardware_class);
+    for (size_t j = 0; j < hardware_class.size(); ++j)
+      filter.add_hardware_class(hardware_class[j]);
+
+    std::vector<std::string> exclude_hardware_class;
+    base::SplitString(test_cases[i].exclude_hardware_class, ',',
+                      &exclude_hardware_class);
+    for (size_t j = 0; j < exclude_hardware_class.size(); ++j)
+      filter.add_exclude_hardware_class(exclude_hardware_class[j]);
+
+    EXPECT_EQ(test_cases[i].expected_result,
+              internal::CheckStudyHardwareClass(
+                  filter, test_cases[i].actual_hardware_class));
+  }
+}
+
 TEST(VariationsStudyFilteringTest, FilterAndValidateStudies) {
   const std::string kTrial1Name = "A";
   const std::string kGroup1Name = "Group1";
@@ -339,7 +398,7 @@ TEST(VariationsStudyFilteringTest, FilterAndValidateStudies) {
   std::vector<ProcessedStudy> processed_studies;
   FilterAndValidateStudies(
       seed, "en-CA", base::Time::Now(), base::Version("20.0.0.0"),
-      Study_Channel_STABLE, Study_FormFactor_DESKTOP, &processed_studies);
+      Study_Channel_STABLE, Study_FormFactor_DESKTOP, "", &processed_studies);
 
   // Check that only the first kTrial1Name study was kept.
   ASSERT_EQ(2U, processed_studies.size());
diff --git a/components/variations/variations_seed_processor.cc b/components/variations/variations_seed_processor.cc
index e155100..e06474a 100644
--- a/components/variations/variations_seed_processor.cc
+++ b/components/variations/variations_seed_processor.cc
@@ -64,10 +64,11 @@ void VariationsSeedProcessor::CreateTrialsFromSeed(
     const base::Time& reference_date,
     const base::Version& version,
     Study_Channel channel,
-    Study_FormFactor form_factor) {
+    Study_FormFactor form_factor,
+    const std::string& hardware_class) {
   std::vector<ProcessedStudy> filtered_studies;
   FilterAndValidateStudies(seed, locale, reference_date, version, channel,
-                           form_factor, &filtered_studies);
+                           form_factor, hardware_class, &filtered_studies);
 
   for (size_t i = 0; i < filtered_studies.size(); ++i)
     CreateTrialFromStudy(filtered_studies[i]);
diff --git a/components/variations/variations_seed_processor.h b/components/variations/variations_seed_processor.h
index f6760ac..dd4d0c8 100644
--- a/components/variations/variations_seed_processor.h
+++ b/components/variations/variations_seed_processor.h
@@ -27,13 +27,15 @@ class VariationsSeedProcessor {
   virtual ~VariationsSeedProcessor();
 
   // Creates field trials from the specified variations |seed|, based on the
-  // specified configuration (locale, current date, version and channel).
+  // specified configuration (locale, current date, version, channel, form
+  // factor and hardware_class).
   void CreateTrialsFromSeed(const VariationsSeed& seed,
                             const std::string& locale,
                             const base::Time& reference_date,
                             const base::Version& version,
                             Study_Channel channel,
-                            Study_FormFactor form_factor);
+                            Study_FormFactor form_factor,
+                            const std::string& hardware_class);
 
  private:
   friend class VariationsSeedProcessorTest;
diff --git a/components/variations/variations_seed_processor_unittest.cc b/components/variations/variations_seed_processor_unittest.cc
index d882aed..833b5e0 100644
--- a/components/variations/variations_seed_processor_unittest.cc
+++ b/components/variations/variations_seed_processor_unittest.cc
@@ -196,7 +196,7 @@ TEST_F(VariationsSeedProcessorTest,
     study1->set_expiry_date(TimeToProtoTime(year_ago));
     seed_processor.CreateTrialsFromSeed(seed, "en-CA", base::Time::Now(),
                                         version, Study_Channel_STABLE,
-                                        Study_FormFactor_DESKTOP);
+                                        Study_FormFactor_DESKTOP, "");
     EXPECT_EQ(kGroup1Name, base::FieldTrialList::FindFullName(kTrialName));
   }
 
@@ -208,7 +208,7 @@ TEST_F(VariationsSeedProcessorTest,
     study2->set_expiry_date(TimeToProtoTime(year_ago));
     seed_processor.CreateTrialsFromSeed(seed, "en-CA", base::Time::Now(),
                                         version, Study_Channel_STABLE,
-                                        Study_FormFactor_DESKTOP);
+                                        Study_FormFactor_DESKTOP, "");
     EXPECT_EQ(kGroup1Name, base::FieldTrialList::FindFullName(kTrialName));
   }
 }
@@ -323,7 +323,7 @@ TEST_F(VariationsSeedProcessorTest, StartsActive) {
   seed_processor.CreateTrialsFromSeed(seed, "en-CA", base::Time::Now(),
                                       base::Version("20.0.0.0"),
                                       Study_Channel_STABLE,
-                                      Study_FormFactor_DESKTOP);
+                                      Study_FormFactor_DESKTOP, "");
 
   // Non-specified and ACTIVATION_EXPLICIT should not start active, but
   // ACTIVATION_AUTO should.
diff --git a/components/variations/variations_seed_simulator.cc b/components/variations/variations_seed_simulator.cc
index 94e4fbb..62b9aaa 100644
--- a/components/variations/variations_seed_simulator.cc
+++ b/components/variations/variations_seed_simulator.cc
@@ -114,10 +114,11 @@ VariationsSeedSimulator::Result VariationsSeedSimulator::SimulateSeedStudies(
     const base::Time& reference_date,
     const base::Version& version,
     Study_Channel channel,
-    Study_FormFactor form_factor) {
+    Study_FormFactor form_factor,
+    const std::string& hardware_class) {
   std::vector<ProcessedStudy> filtered_studies;
   FilterAndValidateStudies(seed, locale, reference_date, version, channel,
-                           form_factor, &filtered_studies);
+                           form_factor, hardware_class, &filtered_studies);
 
   return ComputeDifferences(filtered_studies);
 }
diff --git a/components/variations/variations_seed_simulator.h b/components/variations/variations_seed_simulator.h
index ef9207b..36110ce 100644
--- a/components/variations/variations_seed_simulator.h
+++ b/components/variations/variations_seed_simulator.h
@@ -58,7 +58,8 @@ class VariationsSeedSimulator {
                              const base::Time& reference_date,
                              const base::Version& version,
                              Study_Channel channel,
-                             Study_FormFactor form_factor);
+                             Study_FormFactor form_factor,
+                             const std::string& hardware_class);
 
  private:
   friend class VariationsSeedSimulatorTest;