Update from https://crrev.com/320343

cc/resources/tile_task_worker_pool_unittest.cc

Index: cc/resources/tile_task_worker_pool_unittest.cc
diff --git a/cc/resources/tile_task_worker_pool_unittest.cc b/cc/resources/tile_task_worker_pool_unittest.cc
index d7cb155ef956c0cd06fd780e57df27916d05f77a..72f9d2097a50ff324b06095d3ae9f15ea682dac9 100644
--- a/cc/resources/tile_task_worker_pool_unittest.cc
+++ b/cc/resources/tile_task_worker_pool_unittest.cc
@@ -28,6 +28,7 @@
 #include "cc/test/test_gpu_memory_buffer_manager.h"
 #include "cc/test/test_shared_bitmap_manager.h"
 #include "cc/test/test_web_graphics_context_3d.h"
+#include "gpu/GLES2/gl2extchromium.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace cc {
@@ -275,6 +276,14 @@ class TileTaskWorkerPoolTest
     return completed_tasks_;
   }
 
+  void LoseContext(ContextProvider* context_provider) {
+    if (!context_provider)
+      return;
+    context_provider->ContextGL()->LoseContextCHROMIUM(
+        GL_GUILTY_CONTEXT_RESET_ARB, GL_INNOCENT_CONTEXT_RESET_ARB);
+    context_provider->ContextGL()->Flush();
+  }
+
  private:
   void Create3dOutputSurfaceAndResourceProvider() {
     output_surface_ = FakeOutputSurface::Create3d(
@@ -404,6 +413,21 @@ TEST_P(TileTaskWorkerPoolTest, LargeResources) {
   RunMessageLoopUntilAllTasksHaveCompleted();
 }
 
+TEST_P(TileTaskWorkerPoolTest, LostContext) {
+  LoseContext(output_surface_->context_provider());
+  LoseContext(output_surface_->worker_context_provider());
+
+  AppendTask(0u);
+  AppendTask(1u);
+  ScheduleTasks();
+
+  RunMessageLoopUntilAllTasksHaveCompleted();
+
+  ASSERT_EQ(2u, completed_tasks().size());
+  EXPECT_FALSE(completed_tasks()[0].canceled);
+  EXPECT_FALSE(completed_tasks()[1].canceled);
+}
+
 INSTANTIATE_TEST_CASE_P(
     TileTaskWorkerPoolTests,
     TileTaskWorkerPoolTest,