list command: can now filter results by supported platform

Added -p option to the list command. This alows filtering results by
supported platforms, e.g.

	wa list workloads -p linux

Also adding missing supported_platforms attribute to various extensions.
If an extension does not have this attribute, the assumption is that it
is supported by all available platforms.

wlauto/commands/list.py

@@ -31,6 +31,8 @@ class ListCommand(Command):
                                        'one of: {}'.format(', '.join(extension_types))),
                                  choices=extension_types)
         self.parser.add_argument('-n', '--name', help='Filter results by the name specified')
+        self.parser.add_argument('-p', '--platform', help='Only list results that are supported by '
+                                                          'the specified platform')
 
     def execute(self, args):
         filters = {}
@@ -39,7 +41,7 @@ class ListCommand(Command):
 
         ext_loader = ExtensionLoader(packages=settings.extension_packages, paths=settings.extension_paths)
         results = ext_loader.list_extensions(args.kind[:-1])
-        if filters:
+        if filters or args.platform:
             filtered_results = []
             for result in results:
                 passed = True
@@ -47,6 +49,8 @@ class ListCommand(Command):
                     if getattr(result, k) != v:
                         passed = False
                         break
+                if passed and args.platform:
+                    passed = check_platform(result, args.platform)
                 if passed:
                     filtered_results.append(result)
         else:  # no filters specified
@@ -57,3 +61,10 @@ class ListCommand(Command):
             for result in sorted(filtered_results, key=lambda x: x.name):
                 output.add_item(get_summary(result), result.name)
             print output.format_data()
+
+
+def check_platform(extension, platform):
+    supported_platforms = getattr(extension, 'supported_platforms', [])
+    if supported_platforms:
+        return platform in supported_platforms
+    return True

wlauto/common/android/workload.py

@@ -144,6 +144,7 @@ class ApkWorkload(Workload):
     view = None
     install_timeout = None
     default_install_timeout = 300
+    supported_platforms = ['android']
 
     parameters = [
         Parameter('uninstall_apk', kind=boolean, default=False,
@@ -304,6 +305,8 @@ class ReventWorkload(Workload):
 
 class AndroidUiAutoBenchmark(UiAutomatorWorkload, AndroidBenchmark):
 
+    supported_platforms = ['android']
+
     def __init__(self, device, **kwargs):
         UiAutomatorWorkload.__init__(self, device, **kwargs)
         AndroidBenchmark.__init__(self, device, _call_super=False, **kwargs)
@@ -357,6 +360,7 @@ class GameWorkload(ApkWorkload, ReventWorkload):
     view = 'SurfaceView'
     install_timeout = 500
     loading_time = 10
+    supported_platforms = ['android']
 
     def __init__(self, device, **kwargs):  # pylint: disable=W0613
         ApkWorkload.__init__(self, device, **kwargs)

wlauto/instrumentation/fps/__init__.py

@@ -70,6 +70,7 @@ class FpsInstrument(Instrument):
                        vsync cycle.
 
     """
+    supported_platforms = ['android']
 
     parameters = [
         Parameter('drop_threshold', kind=numeric, default=5,

wlauto/workloads/applaunch/__init__.py

@@ -60,6 +60,7 @@ class ApplaunchWorkload(Workload):
     Measures the time and energy used in launching an application.
 
     """
+    supported_platforms = ['android']
 
     parameters = [
         Parameter('app', default='browser', allowed_values=['calculator', 'browser', 'calendar'],

wlauto/workloads/audio/__init__.py

@@ -33,6 +33,7 @@ class Audio(Workload):
     it plays Canon_in_D_Pieano.mp3 for 30 seconds.
 
     """
+    supported_platforms = ['android']
 
     parameters = [
         Parameter('duration', kind=int, default=30,

wlauto/workloads/dex2oat/__init__.py

@@ -39,6 +39,7 @@ class Dex2oatBenchmark(Workload):
 
         """
 
+    supported_platforms = ['android']
     command_template = 'dex2oat --dex-file={} --oat-file={} --instruction-set={} --dump-timing'
     run_timeout = 5 * 60
 

wlauto/workloads/homescreen/__init__.py

@@ -28,6 +28,7 @@ class HomeScreen(Workload):
     specified duration.
 
     """
+    supported_platforms = ['android']
 
     parameters = [
         Parameter('duration', kind=int, default=20,

wlauto/workloads/power_loadtest/__init__.py

@@ -42,6 +42,7 @@ class PowerLoadtest(Workload):
     See: https://www.chromium.org/chromium-os/testing/power-testing
 
     '''
+    supported_platforms = ['chromeos']
 
     parameters = [
         Parameter('board', default=os.getenv('BOARD'),

wlauto/workloads/video/__init__.py

@@ -45,6 +45,7 @@ class VideoWorkload(Workload):
     .. _Big Buck Bunny: http://www.bigbuckbunny.org/
 
     """
+    supported_platforms = ['android']
 
     parameters = [
         Parameter('play_duration', kind=int, default=20,