[android] Clear content_browsertests profile after each run.

build/android/pylib/gtest/test_runner.py

Index: build/android/pylib/gtest/test_runner.py
diff --git a/build/android/pylib/gtest/test_runner.py b/build/android/pylib/gtest/test_runner.py
index 2a93e37532c828045c54011ebc0a77012985c964..6e47dd09e0d4fb4fccde85e86b652dd1373e0c1f 100644
--- a/build/android/pylib/gtest/test_runner.py
+++ b/build/android/pylib/gtest/test_runner.py
@@ -187,5 +187,10 @@ class TestRunner(base_test_runner.BaseTestRunner):
   #override
   def TearDown(self):
     """Cleans up the test enviroment for the test suite."""
+    # Content shell creates a profile on the sdscard which accumulates cache
+    # files over time.
+    self.adb.RunShellCommand('rm -r ' +
+        os.path.join(self.adb.GetExternalStorage(), 'content_shell'),
+        timeout_time=60 * 2)
     self.tool.CleanUpEnvironment()
     super(TestRunner, self).TearDown()