[Predator] Switch from scorer-based classifier to loglinear classifier.

appengine/findit/crash/findit_for_chromecrash.py

Index: appengine/findit/crash/findit_for_chromecrash.py
diff --git a/appengine/findit/crash/findit_for_chromecrash.py b/appengine/findit/crash/findit_for_chromecrash.py
index dcb2d3c57f66a6587dfd3fdb607d2be89dc16b52..f97ffec9aa7168eb25aef967f39a5be3a1f173dd 100644
--- a/appengine/findit/crash/findit_for_chromecrash.py
+++ b/appengine/findit/crash/findit_for_chromecrash.py
@@ -8,11 +8,16 @@ from google.appengine.ext import ndb
 
 from common import appengine_util
 from crash import detect_regression_range
-from crash.changelist_classifier import ChangelistClassifier
 from crash.chromecrash_parser import ChromeCrashParser
 from crash.component import Component
 from crash.component_classifier import ComponentClassifier
 from crash.findit import Findit
+from crash.loglinear.changelist_classifier import LogLinearChangelistClassifier
+from crash.loglinear.changelist_features.touch_crashed_file_meta import (
+    TouchCrashedFileMetaFeature)
+from crash.loglinear.feature import WrapperMetaFeature
+from crash.loglinear.weight import MetaWeight
+from crash.loglinear.weight import Weight
 from crash.predator import Predator
 from crash.project import Project
 from crash.project_classifier import ProjectClassifier
@@ -34,6 +39,7 @@ _FRACAS_FEEDBACK_URL_TEMPLATE = 'https://%s/crash/fracas-result-feedback?key=%s'
 # from historical_metadata (when historical_metadata is provided and
 # regression_range is not).
 
+
 class FinditForChromeCrash(Findit):
   """Find culprits for crash reports from the Chrome Crash server."""
 
@@ -52,29 +58,40 @@ class FinditForChromeCrash(Findit):
   # entirely, by passing the relevant data as arguments to this constructor.
   def __init__(self, get_repository):
     super(FinditForChromeCrash, self).__init__(get_repository)
-    project_classifier_config = CrashConfig.Get().project_classifier
-    component_classifier_config = CrashConfig.Get().component_classifier
 
-    self._stacktrace_parser = ChromeCrashParser()
+    # TODO(http://crbug.com/687670): Move meta weight initial value to config.
+    meta_weight = MetaWeight({
+        'TouchCrashedFileMeta': MetaWeight({
+            'MinDistance': Weight(1.),
+            'TopFrameIndex': Weight(1.),
+            'TouchCrashedFile': Weight(1.),
+        })
+    })
+    meta_feature = WrapperMetaFeature(
+        [TouchCrashedFileMetaFeature(get_repository)])
 
+    project_classifier_config = CrashConfig.Get().project_classifier
     projects = [Project(name, path_regexs, function_regexs, host_directories)
                 for name, path_regexs, function_regexs, host_directories
                 in project_classifier_config['project_path_function_hosts']]
+    component_classifier_config = CrashConfig.Get().component_classifier
     components = [Component(component_name, path_regex, function_regex)
                   for path_regex, function_regex, component_name
-                  in component_classifier_config['path_function_component']],
-    # The top_n is the number of components we should return as
-    # components suggestion results.
-    # TODO(http://crbug.com/679964) Deprecate the scorer-based changelist
-    # classifier and use loglinear model instead.
+                  in component_classifier_config['path_function_component']]
+    # The top_n is the number of frames we want to check to get component or
+    # project classifications.
     self._predator = Predator(
-        cl_classifier = ChangelistClassifier(get_repository),
+        cl_classifier = LogLinearChangelistClassifier(get_repository,
+                                                      meta_feature,
+                                                      meta_weight),
         component_classifier = ComponentClassifier(
             components, component_classifier_config['top_n']),
         project_classifier = ProjectClassifier(
             projects, project_classifier_config['top_n'],
             project_classifier_config['non_chromium_project_rank_priority']))
 
+    self._stacktrace_parser = ChromeCrashParser()
+
   def _InitializeAnalysis(self, model, crash_data):
     super(FinditForChromeCrash, self)._InitializeAnalysis(model, crash_data)
     # TODO(wrengr): see Note#1