Clear the error request in ErrorRequestCoordinator if it’s running.

Previously we’d never clear the error request which could lead to a
StateVerifier exception or an object pooling error because 
primary.isLoadFailed() would always return false because the state would
be reset from failed to cleared in the call to primarly.clear() on the 
line immediately above the check.

Fixes #2767.

instrumentation/src/androidTest/java/com/bumptech/glide/ErrorHandlingTest.java

@@ -23,10 +23,13 @@
 import com.bumptech.glide.load.engine.Resource;
 import com.bumptech.glide.load.engine.executor.GlideExecutor;
 import com.bumptech.glide.load.engine.executor.GlideExecutor.UncaughtThrowableStrategy;
+import com.bumptech.glide.request.FutureTarget;
 import com.bumptech.glide.request.RequestListener;
 import com.bumptech.glide.test.ConcurrencyHelper;
 import com.bumptech.glide.test.ResourceIds;
 import com.bumptech.glide.test.TearDownGlide;
+import com.bumptech.glide.test.WaitModelLoader;
+import com.bumptech.glide.test.WaitModelLoader.WaitModel;
 import java.io.File;
 import java.util.concurrent.CountDownLatch;
 import org.junit.Before;
@@ -106,6 +109,30 @@ public void load_whenLoadSucceeds_butEncoderFails_doesNotCallOnLoadFailed()
         .onLoadFailed(any(GlideException.class), any(), anyDrawableTarget(), anyBoolean());
   }
 
+  @Test
+  public void clearRequest_withError_afterPrimaryFails_clearsErrorRequest()
+      throws InterruptedException {
+    WaitModel<Integer> errorModel = WaitModelLoader.Factory.waitOn(ResourceIds.raw.canonical);
+
+    FutureTarget<Drawable> target =
+        Glide.with(context)
+            .load((Object) null)
+            .error(
+                Glide.with(context)
+                    .load(errorModel)
+                    .listener(requestListener))
+            .submit();
+
+    Glide.with(context).clear(target);
+    errorModel.countDown();
+
+    // Make sure any pending requests run.
+    concurrency.pokeMainThread();
+    Glide.tearDown();
+    // Make sure that any callbacks posted back to the main thread run.
+    concurrency.pokeMainThread();
+  }
+
   private static final class WaitForErrorStrategy implements UncaughtThrowableStrategy {
     final CountDownLatch latch = new CountDownLatch(1);
     @Nullable Throwable error = null;

library/src/main/java/com/bumptech/glide/request/ErrorRequestCoordinator.java

@@ -43,7 +43,9 @@ public void pause() {
   @Override
   public void clear() {
     primary.clear();
-    if (primary.isFailed()) {
+    // Don't check primary.isFailed() here because it will have been reset by the clear call
+    // immediately before this.
+    if (error.isRunning()) {
       error.clear();
     }
   }

library/src/test/java/com/bumptech/glide/request/ErrorRequestCoordinatorTest.java

@@ -80,8 +80,9 @@ public void clear_whenPrimaryHasNotFailed_doesNotClearError() {
   }
 
   @Test
-  public void clear_whenPrimaryHasFailed_clearsError() {
+  public void clear_whenPrimaryHasFailed_errorIsRunning_clearsError() {
     when(primary.isFailed()).thenReturn(true);
+    when(error.isRunning()).thenReturn(true);
     coordinator.clear();
     verify(error).clear();
   }
@@ -93,6 +94,14 @@ public void clear_whenPrimaryHasFailed_clearsPrimary() {
     verify(primary).clear();
   }
 
+  @Test
+  public void clear_whenErrorIsRunning_clearsError() {
+    when(error.isRunning()).thenReturn(true);
+    coordinator.clear();
+
+    verify(error).clear();
+  }
+
   @Test
   public void isPaused_primaryNotFailed_primaryNotPaused_returnsFalse() {
     assertThat(coordinator.isPaused()).isFalse();