[Android] Fix android_profiling_helper pulling lib from device.

Telemetry's android_profiling_helper currently fails when trying to pull
a library from the device if the library doesn't already exist on the host
(read: most if not all of the time). This patch fixes that.

BUG=489969

Review URL: https://codereview.chromium.org/1142413002

Cr-Commit-Position: refs/heads/master@{#330744}

tools/telemetry/telemetry/core/platform/profiler/android_profiling_helper.py

@@ -204,8 +204,15 @@ def CreateSymFs(device, symfs_dir, libraries, use_symlinks=True):
       # the profiler can at least use the public symbols of that library. To
       # speed things up, only pull files that don't match copies we already
       # have in the symfs.
-      if (md5sum.CalculateHostMd5Sums([output_lib])[0] !=
-          md5sum.CalculateDeviceMd5Sums([lib])[0]):
+      if not os.path.exists(output_lib):
+        pull = True
+      else:
+        host_md5sums = md5sum.CalculateHostMd5Sums([output_lib])
+        device_md5sums = md5sum.CalculateDeviceMd5Sums([lib], device)
+        pull = (not host_md5sums or not device_md5sums
+                or host_md5sums[0] != device_md5sums[0])
+
+      if pull:
         logging.info('Pulling %s to %s', lib, output_lib)
         device.PullFile(lib, output_lib)
 
@@ -260,10 +267,22 @@ def GetToolchainBinaryPath(library_file, binary_name):
     return None
   toolchain_version = toolchain_version.group(1)
 
-  path = os.path.join(util.GetChromiumSrcDir(), 'third_party', 'android_tools',
-                      'ndk', 'toolchains',
-                      '%s-%s' % (toolchain_config, toolchain_version),
-                      'prebuilt', '%s-%s' % (host_os, host_machine), 'bin',
+  toolchain_path = os.path.abspath(os.path.join(
+      util.GetChromiumSrcDir(), 'third_party', 'android_tools', 'ndk',
+      'toolchains', '%s-%s' % (toolchain_config, toolchain_version)))
+  if not os.path.exists(toolchain_path):
+    logging.warning(
+        'Unable to find toolchain binary %s: toolchain not found at %s',
+        binary_name, toolchain_path)
+    return None
+
+  path = os.path.join(
+      toolchain_path, 'prebuilt', '%s-%s' % (host_os, host_machine), 'bin',
       '%s-%s' % (toolchain_config, binary_name))
-  path = os.path.abspath(path)
-  return path if os.path.exists(path) else None
+  if not os.path.exists(path):
+    logging.warning(
+        'Unable to find toolchain binary %s: binary not found at %s',
+        binary_name, path)
+    return None
+
+  return path

tools/telemetry/telemetry/core/platform/profiler/android_profiling_helper_unittest.py

@@ -96,9 +96,7 @@ class TestAndroidProfilingHelperTabTestCase(tab_test_case.TabTestCase):
     browser_backend = self._browser._browser_backend
     self._device = browser_backend._adb.device()
 
-  # Test fails: crbug.com/437081
-  # @decorators.Enabled('android')
-  @decorators.Disabled
+  @decorators.Enabled('android')
   def testCreateSymFs(self):
     # pylint: disable=W0212
     browser_pid = self._browser._browser_backend.pid
@@ -115,7 +113,7 @@ class TestAndroidProfilingHelperTabTestCase(tab_test_case.TabTestCase):
       # Check that we have kernel symbols.
       assert os.path.exists(kallsyms)
 
-      is_unstripped = re.compile(r'^/data/app/.*\.so$')
+      is_unstripped = re.compile(r'^/data/app(-lib)?/.*\.so$')
       has_unstripped = False
 
       # Check that all requested libraries are present.
@@ -137,4 +135,4 @@ class TestAndroidProfilingHelperTabTestCase(tab_test_case.TabTestCase):
       self._device.PullFile('/system/lib/libc.so', libc.name)
       path = android_profiling_helper.GetToolchainBinaryPath(libc.name,
                                                              'objdump')
-      assert os.path.exists(path)
+      assert path and os.path.exists(path)