[Android Buildbot] Install ContentShell.apk before running GPU tests.

BUG=256576

Review URL: https://chromiumcodereview.appspot.com/23936010

git-svn-id: http://src.chromium.org/svn/trunk/src/build@223230 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

android/buildbot/bb_device_steps.py

@@ -316,7 +316,8 @@ def RunWebRTCTests(options):
   RunTestSuites(options, gtest_config.WEBRTC_TEST_SUITES)
 
 
-def RunGPUTests(_):
+def RunGPUTests(options):
+  InstallApk(options, INSTRUMENTATION_TESTS['ContentShell'], False)
   bb_annotations.PrintNamedStep('gpu_tests')
   RunCmd(['content/test/gpu/run_gpu_test',
           '--browser=android-content-shell', 'pixel'])