Telemetry: makes profilers a bit more generic.

tools/telemetry/telemetry/core/platform/profiler/perf_profiler.py

Index: tools/telemetry/telemetry/core/platform/profiler/perf_profiler.py
diff --git a/tools/telemetry/telemetry/core/platform/profiler/perf_profiler.py b/tools/telemetry/telemetry/core/platform/profiler/perf_profiler.py
index eb737440ff015776059472581235a58f18502f8e..18074f28e34a661f229360ea8d6c73b9eb1291d3 100644
--- a/tools/telemetry/telemetry/core/platform/profiler/perf_profiler.py
+++ b/tools/telemetry/telemetry/core/platform/profiler/perf_profiler.py
@@ -10,34 +10,16 @@ import tempfile
 from telemetry.core.platform import profiler
 
 
-class PerfProfiler(profiler.Profiler):
-
-  def __init__(self, browser_backend, pid, output_path):
-    super(PerfProfiler, self).__init__(output_path)
-    self._browser_backend = browser_backend
+class _SingleProcessPerfProfiler(object):
+  """An internal class for using perf for a given process."""
+  def __init__(self, pid, output_file):
+    self._output_file = output_file
     self._tmp_output_file = tempfile.NamedTemporaryFile('w', 0)
     self._proc = subprocess.Popen(
         ['perf', 'record', '--call-graph',
-         '--pid', str(pid), '--output', self.output_path],
+         '--pid', str(pid), '--output', output_file],
         stdout=self._tmp_output_file, stderr=subprocess.STDOUT)
 
-  @classmethod
-  def name(cls):
-    return 'perf'
-
-  @classmethod
-  def is_supported(cls, options):
-    if (sys.platform != 'linux2'
-        or options.browser_type.startswith('android')
-        or options.browser_type.startswith('cros')):
-      return False
-    try:
-      return not subprocess.Popen(['perf', '--version'],
-                                  stderr=subprocess.STDOUT,
-                                  stdout=subprocess.PIPE).wait()
-    except OSError:
-      return False
-
   def CollectProfile(self):
     self._proc.send_signal(signal.SIGINT)
     exit_code = self._proc.wait()
@@ -47,11 +29,9 @@ class PerfProfiler(profiler.Profiler):
             'perf failed with exit code %d. Output:\n%s' % (exit_code,
                                                             self._GetStdOut()))
     finally:
-      self._proc = None
       self._tmp_output_file.close()
-
     print 'To view the profile, run:'
-    print '  perf report -i %s' % self.output_path
+    print '  perf report -i %s' % self._output_file
 
   def _GetStdOut(self):
     self._tmp_output_file.flush()
@@ -60,3 +40,36 @@ class PerfProfiler(profiler.Profiler):
         return f.read()
     except IOError:
       return ''
+
+
+class PerfProfiler(profiler.Profiler):
+
+  def __init__(self, browser_backend, platform_backend, output_path):
+    super(PerfProfiler, self).__init__(
+        browser_backend, platform_backend, output_path)
+    process_output_file_map = self._GetProcessOutputFileMap()
+    self._process_profilers = []
+    for pid, output_file in process_output_file_map.iteritems():
+      self._process_profilers.append(
+          _SingleProcessPerfProfiler(pid, output_file))
+
+  @classmethod
+  def name(cls):
+    return 'perf'
+
+  @classmethod
+  def is_supported(cls, options):
+    if (sys.platform != 'linux2'
+        or options.browser_type.startswith('android')
+        or options.browser_type.startswith('cros')):
+      return False
+    try:
+      return not subprocess.Popen(['perf', '--version'],
+                                  stderr=subprocess.STDOUT,
+                                  stdout=subprocess.PIPE).wait()
+    except OSError:
+      return False
+
+  def CollectProfile(self):
+    for single_process in self._process_profilers:
+      single_process.CollectProfile()