Make telemetry platform a singleton

tools/telemetry/telemetry/core/backends/chrome/android_browser_finder.py

Index: tools/telemetry/telemetry/core/backends/chrome/android_browser_finder.py
diff --git a/tools/telemetry/telemetry/core/backends/chrome/android_browser_finder.py b/tools/telemetry/telemetry/core/backends/chrome/android_browser_finder.py
index 7389452c45067170352f815e3e430fdf6ac806a4..d51c3387f49c9434261360f7b8f3d1a9de512908 100644
--- a/tools/telemetry/telemetry/core/backends/chrome/android_browser_finder.py
+++ b/tools/telemetry/telemetry/core/backends/chrome/android_browser_finder.py
@@ -17,6 +17,7 @@ from telemetry.core import possible_browser
 from telemetry.core import util
 from telemetry.core.backends import adb_commands
 from telemetry.core.backends.chrome import android_browser_backend
+from telemetry.core import platform as platform_module
 from telemetry.core.platform import android_platform_backend
 from telemetry.core.platform.profiler import monsoon
 
@@ -98,23 +99,26 @@ class PossibleAndroidBrowser(possible_browser.PossibleBrowser):
   def __repr__(self):
     return 'PossibleAndroidBrowser(browser_type=%s)' % self.browser_type
 
-  @property
-  @decorators.Cache
-  def _platform_backend(self):
-    return android_platform_backend.AndroidPlatformBackend(
+  def _InitPlatformIfNeeded(self):
+    if self._platform:
+      return
+    platform_backend = android_platform_backend.AndroidPlatformBackend(
         self._backend_settings.adb.device(),
         self.finder_options.no_performance_mode)
+    self._platform = platform_module.Platform(platform_backend)
 
   def Create(self):
+    self._InitPlatformIfNeeded()
+    not_linux = platform.GetHostPlatformName() != 'linux'
     use_rndis_forwarder = (self.finder_options.android_rndis or
                            self.finder_options.browser_options.netsim or
-                           platform.GetHostPlatform().GetOSName() != 'linux')
+                           not_linux)
     backend = android_browser_backend.AndroidBrowserBackend(
         self.finder_options.browser_options, self._backend_settings,
         use_rndis_forwarder,
         output_profile_path=self.finder_options.output_profile_path,
         extensions_to_load=self.finder_options.extensions_to_load)
-    b = browser.Browser(backend, self._platform_backend)
+    b = browser.Browser(backend, self._platform)
     return b
 
   def SupportsOptions(self, finder_options):