Revert "Record the GPU watchdog arm_disarm_counter in the main thread"

This reverts commit 15ab8559.

Reason for revert: <The data has been collected from the crash dumps. Debugging code is no longer needed. >

Original change's description:
> Record the GPU watchdog arm_disarm_counter in the main thread
> 
> It is for the debugging purpose only and it wil have a performance impact.
> The code will be removed immediately once valid crash dumps are collected.
> 
> Bug: 885066,885066
> Change-Id: Ie8761ed4e6050a07e76af0a030b67dab5bb011e8
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2129028
> Commit-Queue: Maggie Chen <magchen@chromium.org>
> Reviewed-by: Zhenyao Mo <zmo@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#756461}

TBR=zmo@chromium.org,magchen@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 885066
Change-Id: If5d439c97c3bf4732297b9a756423c18f024b865
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2144812Reviewed-by: Maggie Chen <magchen@chromium.org>
Commit-Queue: Maggie Chen <magchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#758004}

gpu/ipc/service/gpu_watchdog_thread_v2.cc

@@ -378,12 +378,7 @@ void GpuWatchdogThreadImplV2::UpdateInitializationFlag() {
 void GpuWatchdogThreadImplV2::Arm() {
   DCHECK(watched_gpu_task_runner_->BelongsToCurrentThread());
 
-  if (hits_termination_.IsSet()) {
-    base::subtle::NoBarrier_AtomicIncrement(&arm_disarm_counter_, 1);
-  } else {
-    arm_disarm_counter_main_thread_ =
-        base::subtle::NoBarrier_AtomicIncrement(&arm_disarm_counter_, 1);
-  }
+  base::subtle::NoBarrier_AtomicIncrement(&arm_disarm_counter_, 1);
 
   // Arm/Disarm are always called in sequence. Now it's an odd number.
   DCHECK(IsArmed());
@@ -392,12 +387,7 @@ void GpuWatchdogThreadImplV2::Arm() {
 void GpuWatchdogThreadImplV2::Disarm() {
   DCHECK(watched_gpu_task_runner_->BelongsToCurrentThread());
 
-  if (hits_termination_.IsSet()) {
-    base::subtle::NoBarrier_AtomicIncrement(&arm_disarm_counter_, 1);
-  } else {
-    arm_disarm_counter_main_thread_ =
-        base::subtle::NoBarrier_AtomicIncrement(&arm_disarm_counter_, 1);
-  }
+  base::subtle::NoBarrier_AtomicIncrement(&arm_disarm_counter_, 1);
 
   // Arm/Disarm are always called in sequence. Now it's an even number.
   DCHECK(!IsArmed());
@@ -407,13 +397,7 @@ void GpuWatchdogThreadImplV2::InProgress() {
   DCHECK(watched_gpu_task_runner_->BelongsToCurrentThread());
 
   // Increment by 2. This is equivalent to Disarm() + Arm().
-
-  if (hits_termination_.IsSet()) {
-    base::subtle::NoBarrier_AtomicIncrement(&arm_disarm_counter_, 2);
-  } else {
-    arm_disarm_counter_main_thread_ =
-        base::subtle::NoBarrier_AtomicIncrement(&arm_disarm_counter_, 2);
-  }
+  base::subtle::NoBarrier_AtomicIncrement(&arm_disarm_counter_, 2);
 
   // Now it's an odd number.
   DCHECK(IsArmed());
@@ -602,10 +586,6 @@ void GpuWatchdogThreadImplV2::DeliberatelyTerminateToRecoverFromHang() {
     return;
   }
 
-  // Debug only. To be deleted
-  hits_termination_.Set();
-  base::debug::Alias(&arm_disarm_counter_main_thread_);
-
 #if defined(OS_WIN)
   if (IsDebuggerPresent())
     return;

gpu/ipc/service/gpu_watchdog_thread_v2.h

@@ -227,11 +227,6 @@ class GPU_IPC_SERVICE_EXPORT GpuWatchdogThreadImplV2
   bool foregrounded_event_ = false;
   bool power_resumed_event_ = false;
 
-  // TODO (magche@): Debugging only. This has a measurable performance impact
-  // and should be removed once valid crash dumps are collected.
-  base::AtomicFlag hits_termination_;
-  base::subtle::Atomic32 arm_disarm_counter_main_thread_ = 0;
-
   // For gpu testing only.
   const bool is_test_mode_;
   // Set by the watchdog thread and Read by the test thread.