Revert of Don't bother running realpath in DeviceUtils._GetChangedAndStaleFiles()

Revert of Don't bother running realpath in DeviceUtils._GetChangedAndStaleFiles() (patchset #2 id:20001 of https://codereview.chromium.org/1300263002/ )

Reason for revert:
md5sum prints realpath, so this is actually still necessary unless we change md5sum to print paths given.

Original issue's description:
> Don't bother running realpath in DeviceUtils._GetChangedAndStaleFiles()
>
> Shaves off a single adb command from managed_install.py (~150ms)
>
> BUG=520082
>
> Committed: https://crrev.com/298f31eca43d36d67f6cbc8b2d2a495c5a625f1d
> Cr-Commit-Position: refs/heads/master@{#345129}

TBR=jbudorick@chromium.org
BUG=520082
Committed: https://crrev.com/f1a986def97afb57d1c4288e99dbfa9e3329e9e1
Cr-Commit-Position: refs/heads/master@{#345674}

[agrieve, 2015-08-26 13:55:29]

Created Revert of Don't bother running realpath in
DeviceUtils._GetChangedAndStaleFiles()

[commit-bot: I haz the power, 2015-08-26 13:55:37]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1306883004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1306883004/1

[commit-bot: I haz the power, 2015-08-26 13:55:38]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-08-26 13:55:38]

No L-G-T-M from a valid reviewer yet. Only full committers are accepted.
Even if an L-G-T-M may have been provided, it was from a non-committer,
_not_ a full super star committer.
See http://www.chromium.org/getting-involved/become-a-committer
Note that this has nothing to do with OWNERS files.

[jbudorick, 2015-08-26 13:55:57]

lgtm

[agrieve, 2015-08-26 13:56:43]

The CQ bit was checked by agrieve@chromium.org

[commit-bot: I haz the power, 2015-08-26 13:56:48]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1306883004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1306883004/1

[commit-bot: I haz the power, 2015-08-26 13:57:26]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-08-26 13:57:26]

Failed to apply patch for build/android/pylib/device/device_utils.py:
While running git apply --index -3 -p1;
  error: patch failed: build/android/pylib/device/device_utils.py:1034
  Falling back to three-way merge...
  Applied patch to 'build/android/pylib/device/device_utils.py' with conflicts.
  U build/android/pylib/device/device_utils.py

Patch:       build/android/pylib/device/device_utils.py
Index: build/android/pylib/device/device_utils.py
diff --git a/build/android/pylib/device/device_utils.py
b/build/android/pylib/device/device_utils.py
index
becd514106bf7b9fe5049fa939f4409fbb202a92..1e2ff8728742a68720e7e069b2ce0c5323c46249
100644
--- a/build/android/pylib/device/device_utils.py
+++ b/build/android/pylib/device/device_utils.py
@@ -1034,12 +1034,21 @@
       2nd element: a list of stale files under device_path, or [] when
         track_stale == False
     """
+    real_host_path = os.path.realpath(host_path)
     try:
-      host_checksums = md5sum.CalculateHostMd5Sums([host_path])
-      interesting_device_paths = [device_path]
-      if not track_stale and os.path.isdir(host_path):
+      real_device_path = self.RunShellCommand(
+          ['realpath', device_path], single_line=True, check_return=True)
+    except device_errors.CommandFailedError:
+      real_device_path = None
+    if not real_device_path:
+      return ([(host_path, device_path)], [])
+
+    try:
+      host_checksums = md5sum.CalculateHostMd5Sums([real_host_path])
+      interesting_device_paths = [real_device_path]
+      if not track_stale and os.path.isdir(real_host_path):
         interesting_device_paths = [
-            posixpath.join(device_path, os.path.relpath(p, host_path))
+            posixpath.join(real_device_path, os.path.relpath(p,
real_host_path))
             for p in host_checksums.keys()]
       device_checksums = md5sum.CalculateDeviceMd5Sums(
           interesting_device_paths, self)
@@ -1048,8 +1057,8 @@
       return ([(host_path, device_path)], [])
 
     if os.path.isfile(host_path):
-      host_checksum = host_checksums.get(host_path)
-      device_checksum = device_checksums.get(device_path)
+      host_checksum = host_checksums.get(real_host_path)
+      device_checksum = device_checksums.get(real_device_path)
       if host_checksum != device_checksum:
         return ([(host_path, device_path)], [])
       else:
@@ -1057,8 +1066,8 @@
     else:
       to_push = []
       for host_abs_path, host_checksum in host_checksums.iteritems():
-        device_abs_path = posixpath.join(
-            device_path, os.path.relpath(host_abs_path, host_path))
+        device_abs_path = '%s/%s' % (
+            real_device_path, os.path.relpath(host_abs_path, real_host_path))
         device_checksum = device_checksums.pop(device_abs_path, None)
         if device_checksum != host_checksum:
           to_push.append((host_abs_path, device_abs_path))

[commit-bot: I haz the power, 2015-08-26 13:57:55]

The CQ bit was unchecked by commit-bot@chromium.org

[agrieve, 2015-08-26 14:09:16]

The CQ bit was checked by agrieve@chromium.org

[agrieve, 2015-08-26 14:09:16]

The patchset sent to the CQ was uploaded after l-g-t-m from
jbudorick@chromium.org
Link to the patchset: https://codereview.chromium.org/1306883004/#ps40001
(title: "manual revert")

[commit-bot: I haz the power, 2015-08-26 14:09:35]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1306883004/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1306883004/40001

[commit-bot: I haz the power, 2015-08-26 14:54:29]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-08-26 14:54:30]

Try jobs failed on following builders:
  linux_chromium_chromeos_ozone_rel_ng on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[agrieve, 2015-08-26 16:04:40]

The CQ bit was checked by agrieve@chromium.org

[commit-bot: I haz the power, 2015-08-26 16:04:55]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1306883004/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1306883004/40001

[commit-bot: I haz the power, 2015-08-26 16:20:02]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-08-26 16:20:03]

Try jobs failed on following builders:
  mac_chromium_rel_ng on tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[jbudorick, 2015-08-26 16:21:53]

On 2015/08/26 at 16:20:03, commit-bot wrote:
> Try jobs failed on following builders:
>   mac_chromium_rel_ng on tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

this is the cloud storage failure that currently has the chromium tree closed.

[agrieve, 2015-08-26 17:26:19]

On 2015/08/26 16:21:53, jbudorick wrote:
> On 2015/08/26 at 16:20:03, commit-bot wrote:
> > Try jobs failed on following builders:
> >   mac_chromium_rel_ng on tryserver.chromium.mac (JOB_FAILED,
>
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)
> 
> this is the cloud storage failure that currently has the chromium tree closed.

Thanks for pointing that out :). Will wait.

[agrieve, 2015-08-26 18:20:49]

The CQ bit was checked by agrieve@chromium.org

[commit-bot: I haz the power, 2015-08-26 18:22:47]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1306883004/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1306883004/40001

[commit-bot: I haz the power, 2015-08-26 18:36:14]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-08-26 18:36:15]

Try jobs failed on following builders:
  mac_chromium_rel_ng on tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[agrieve, 2015-08-26 20:19:12]

The CQ bit was checked by agrieve@chromium.org

[commit-bot: I haz the power, 2015-08-26 20:20:34]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1306883004/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1306883004/40001

[commit-bot: I haz the power, 2015-08-26 21:06:21]

Committed patchset #2 (id:40001)

[commit-bot: I haz the power, 2015-08-26 21:07:59]

Patchset 2 (id:??) landed as
https://crrev.com/f1a986def97afb57d1c4288e99dbfa9e3329e9e1
Cr-Commit-Position: refs/heads/master@{#345674}

[agrieve, 2015-08-27 03:25:12]

A revert of this CL (patchset #2 id:40001) has been created in
https://codereview.chromium.org/1307393004/ by agrieve@chromium.org.

The reason for reverting is: Reland with md5sum tool changes to match..