Fix errorprone StaticGuardedByInstance warnings

Fix errorprone StaticGuardedByInstance warnings and make
sure it is treated as error after this CL.

http://errorprone.info/bugpattern/StaticGuardedByInstance

Bug: 803625
Change-Id: Ica786979670c8ec58c07691122e225acc56e62df
Reviewed-on: https://chromium-review.googlesource.com/961041
Commit-Queue: agrieve <agrieve@chromium.org>
Reviewed-by: agrieve <agrieve@chromium.org>
Cr-Commit-Position: refs/heads/master@{#543078}

base/test/android/java/src/org/chromium/base/JavaHandlerThreadHelpers.java

@@ -10,22 +10,23 @@ import org.chromium.base.annotations.CalledByNative;
 import org.chromium.base.annotations.CalledByNativeUnchecked;
 import org.chromium.base.annotations.JNINamespace;
 
+import java.util.concurrent.atomic.AtomicBoolean;
+
 @JNINamespace("base::android")
 class JavaHandlerThreadHelpers {
     private static class TestException extends Exception {}
 
-    private static boolean sTaskExecuted;
     // This is executed as part of base_unittests. This tests that JavaHandlerThread can be used
     // by itself without attaching to its native peer.
     @CalledByNative
     private static JavaHandlerThread testAndGetJavaHandlerThread() {
-        sTaskExecuted = false;
+        final AtomicBoolean taskExecuted = new AtomicBoolean();
         final Object lock = new Object();
         Runnable runnable = new Runnable() {
             @Override
             public void run() {
                 synchronized (lock) {
-                    sTaskExecuted = true;
+                    taskExecuted.set(true);
                     lock.notifyAll();
                 }
             }
@@ -37,7 +38,7 @@ class JavaHandlerThreadHelpers {
         Handler handler = new Handler(thread.getLooper());
         handler.post(runnable);
         synchronized (lock) {
-            while (!sTaskExecuted) {
+            while (!taskExecuted.get()) {
                 try {
                     lock.wait();
                 } catch (InterruptedException e) {

build/android/gyp/javac.py

@@ -35,8 +35,6 @@ ERRORPRONE_WARNINGS_TO_TURN_OFF = [
   'AssertionFailureIgnored',
   # TODO(crbug.com/803589): Follow steps in bug.
   'MissingFail',
-  # TODO(crbug.com/803625): Follow steps in bug.
-  'StaticGuardedByInstance',
   # Android platform default is always UTF-8.
   # https://developer.android.com/reference/java/nio/charset/Charset.html#defaultCharset()
   'DefaultCharset',
@@ -98,6 +96,7 @@ ERRORPRONE_WARNINGS_TO_ERROR = [
   'MissingOverride',
   'NarrowingCompoundAssignment',
   'ParameterName',
+  'StaticGuardedByInstance',
   'StaticQualifiedUsingExpression',
   'UseCorrectAssertInTests',
 ]