Revert "Do not use the accelerometer device file when it's failed to read"

This reverts commit 42f6f938.

Reason for revert: 
1- We need to trigger event before reading
2- Reading one byte will make next reading unaligned.
3- The error was due to invalid group setting, fixed since.

Original change's description:
> Do not use the accelerometer device file when it's failed to read
>
> On some system / device configuration, the accelerometer device
> file exists but can't be read by the browser process. When this
> happens, it generates error log repeatedly, which is not great.
>
> This CL tries to address this issue in a way. On initializing
> accelerometer configuration, it tries to read the device file
> at that time, and when it fails to read, it just stops the
> initialization and reports an error message. This happens once,
> and does not generate repeated logs.
>
> Also, when an error happens, now it can obtain the errno and
> print it as a part of the log, so it would be more understandable
> why it fails. On my case, it is just permission denied, for some
> reasons.
>
> Bug: 1134527
> Test: manually with nautilus device in the lab
> Change-Id: Ib9823631a70fc54d3e3abc35067aff56a7d7ee50
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2454840
> Reviewed-by: Min Chen <minch@chromium.org>
> Reviewed-by: James Cook <jamescook@chromium.org>
> Commit-Queue: Jun Mukai <mukai@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#814780}

TBR=jamescook@chromium.org,mukai@chromium.org,minch@chromium.org,chenghaoyang@chromium.org

Change-Id: Icd2a780a14bd4e12358053f150a37bd3d7f46f75
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 1134527,1133429
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2461648Reviewed-by: Jun Mukai <mukai@chromium.org>
Commit-Queue: Gwendal Grignou <gwendal@chromium.org>
Auto-Submit: Gwendal Grignou <gwendal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#815187}

ash/accelerometer/accelerometer_reader.cc

@@ -17,7 +17,6 @@
 #include "base/files/file_enumerator.h"
 #include "base/files/file_util.h"
 #include "base/location.h"
-#include "base/logging.h"
 #include "base/memory/singleton.h"
 #include "base/numerics/math_constants.h"
 #include "base/observer_list_threadsafe.h"
@@ -616,21 +615,12 @@ bool AccelerometerFileReader::InitializeAccelerometer(
     }
     configuration_.scale[config_index][i] = scale;
   }
-  base::FilePath path =
-      base::FilePath(kAccelerometerDevicePath).Append(name.BaseName());
-  char try_reading;
-  if (base::ReadFile(path, &try_reading, 1) < 0) {
-    logging::SystemErrorCode err_code = logging::GetLastSystemErrorCode();
-    LOG(ERROR) << "Failed to read " << path
-               << " error: " << logging::SystemErrorCodeToString(err_code);
-    return false;
-  }
-
   configuration_.has[config_index] = true;
   configuration_.count++;
 
   ReadingData reading_data;
-  reading_data.path = path;
+  reading_data.path =
+      base::FilePath(kAccelerometerDevicePath).Append(name.BaseName());
   reading_data.sources.push_back(
       static_cast<AccelerometerSource>(config_index));
 
@@ -711,11 +701,9 @@ void AccelerometerFileReader::ReadFileAndNotify() {
     char reading[reading_size];
     int bytes_read = base::ReadFile(reading_data.path, reading, reading_size);
     if (bytes_read < reading_size) {
-      logging::SystemErrorCode err_code = logging::GetLastSystemErrorCode();
       LOG(ERROR) << "Accelerometer Read " << bytes_read << " byte(s), expected "
                  << reading_size << " bytes from accelerometer "
-                 << reading_data.path.MaybeAsASCII()
-                 << " error: " << logging::SystemErrorCodeToString(err_code);
+                 << reading_data.path.MaybeAsASCII();
       return;
     }
     for (AccelerometerSource source : reading_data.sources) {