Make runtest wait for instrumentation install before running test.

This attempts to address bug 1872940 where runtest will attempt to
run the test before all the new packages pushed via adb sync are
actually installed. This won't completely fix the bug in all cases,
but hopefully will help most situations.

testrunner/adb_interface.py

@@ -317,7 +317,44 @@ class AdbInterface:
     if not pm_found:
       raise errors.WaitForResponseTimedOutError(
           "Package manager did not respond after %s seconds" % wait_time)
-    
+
+  def WaitForInstrumentation(self, package_name, runner_name, wait_time=120):
+    """Waits for given instrumentation to be present on device
+
+    Args:
+      wait_time: time in seconds to wait
+
+    Raises:
+      WaitForResponseTimedOutError if wait_time elapses and instrumentation
+      still not present.
+    """
+    instrumentation_path = "%s/%s" % (package_name, runner_name)
+    logger.Log("Waiting for instrumentation to be present")
+    # Query the package manager
+    inst_found = False
+    attempts = 0
+    wait_period = 5
+    while not inst_found and (attempts*wait_period) < wait_time:
+      # assume the 'adb shell pm list instrumentation'
+      # return 'instrumentation: something' in the success case
+      try:
+        output = self.SendShellCommand("pm list instrumentation | grep %s"
+                                       % instrumentation_path, retry_count=1)
+        if "instrumentation:" in output:
+          inst_found = True
+      except errors.AbortError, e:
+        # ignore
+        pass
+      if not inst_found:
+        time.sleep(wait_period)
+        attempts += 1
+    if not inst_found:
+      logger.Log(
+          "Could not find instrumentation %s on device. Does the "
+          "instrumentation in test's AndroidManifest.xml match definition"
+          "in test_defs.xml?" % instrumentation_path)
+      raise errors.WaitForResponseTimedOutError()
+
   def Sync(self, retry_count=3):
     """Perform a adb sync.