skpbench: support pixel phone

Adds a script for pixel hardware with conservatively low clocks.

Bug: skia:
Change-Id: I1ade703ab9f0b4aefc9cf630e3d2efb996afd69f
Reviewed-on: https://skia-review.googlesource.com/62343
Reviewed-by: Eric Boren <borenet@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>
diff --git a/tools/skpbench/_hardware_pixel_c.py b/tools/skpbench/_hardware_pixel_c.py
index a1cd17a..cdd9ff6 100644
--- a/tools/skpbench/_hardware_pixel_c.py
+++ b/tools/skpbench/_hardware_pixel_c.py
@@ -15,13 +15,14 @@
     HardwareAndroid.__init__(self, adb)
 
   def __enter__(self):
+    HardwareAndroid.__enter__(self)
     self._lock_clocks()
-    return HardwareAndroid.__enter__(self)
+    return self
 
   def __exit__(self, exception_type, exception_value, exception_traceback):
+    self._unlock_clocks()
     HardwareAndroid.__exit__(self, exception_type,
                              exception_value, exception_traceback)
-    self._unlock_clocks()
 
   def filter_line(self, line):
     JUNK = ['NvRmPrivGetChipPlatform: Could not read platform information',
@@ -109,8 +110,3 @@
       [Expectation(str, exact_value=GPU_EMC_PROFILE, name='gpu/emc profile')]
 
     Expectation.check_all(expectations, result.splitlines())
-
-  def sleep(self, sleeptime):
-    self._unlock_clocks()
-    HardwareAndroid.sleep(self, sleeptime)
-    self._lock_clocks()