Revert of Move remote platforms creation logic from android_browser_finder to platform

tools/telemetry/telemetry/core/platform/__init__.py

Index: tools/telemetry/telemetry/core/platform/__init__.py
diff --git a/tools/telemetry/telemetry/core/platform/__init__.py b/tools/telemetry/telemetry/core/platform/__init__.py
index d18323a30133ae67745c8c9912915dbe187403ef..80bf4932fb8135a83aec4b1b8276526a0b363f9c 100644
--- a/tools/telemetry/telemetry/core/platform/__init__.py
+++ b/tools/telemetry/telemetry/core/platform/__init__.py
@@ -6,9 +6,9 @@
 import os
 import sys
 
-from telemetry.core import discover
-from telemetry.core import util
-from telemetry.core.platform import platform_backend as platform_backend_module
+from telemetry.core.platform import cros_device
+from telemetry.core.platform import cros_interface
+from telemetry.core.platform import cros_platform_backend
 from telemetry.core.platform import profiling_controller
 from telemetry.core.platform import tracing_controller
 
@@ -34,8 +34,8 @@
   if _host_platform:
     return
   if _IsRunningOnCrosDevice():
-    from telemetry.core.platform import cros_platform_backend
-    backend = cros_platform_backend.CrosPlatformBackend()
+    backend = cros_platform_backend.CrosPlatformBackend(
+        cros_interface.CrOSInterface())
   elif sys.platform.startswith('linux'):
     from telemetry.core.platform import linux_platform_backend
     backend = linux_platform_backend.LinuxPlatformBackend()
@@ -61,22 +61,20 @@
     Args:
       device: a device.Device instance.
   """
-  if device.guid in _remote_platforms:
-    return _remote_platforms[device.guid]
-  try:
-    platform_backend = None
-    platform_dir = os.path.dirname(os.path.realpath(__file__))
-    for platform_backend_class in discover.DiscoverClasses(
-        platform_dir, util.GetTelemetryDir(),
-        platform_backend_module.PlatformBackend).itervalues():
-      if platform_backend_class.SupportsDevice(device):
-        platform_backend = platform_backend_class(device)
-        _remote_platforms[device.guid] = Platform(platform_backend)
-        return _remote_platforms[device.guid]
-    return None
-  except Exception:
-    logging.error('Fail to create platform instance for %s.', device.name)
-    raise
+  if device.guid not in _remote_platforms:
+    try:
+      if isinstance(device, cros_device.CrOSDevice):
+        cri = cros_interface.CrOSInterface(
+            device.host_name, device.ssh_identity)
+        cri.TryLogin()
+        _remote_platforms[device.guid] = (
+            Platform(cros_platform_backend.CrosPlatformBackend(cri)))
+      else:
+        raise ValueError('Unsupported device type')
+    except:
+      logging.error('Fail to create platform instance for %s.', device.name)
+      raise
+  return _remote_platforms[device.guid]
 
 
 class Platform(object):